Thank you for posting this. As a lifelong Pontiac person, it amazes me how many people who don't even own a Pontiac want to argue with me over the whole "Big Block" thing. For those utterly preoccupied with size, there's "Large Journal" 421-455 and "Small Journal" 400-down referring to the 3.25" or 3" crankshaft journal size. I've given up trying to convince the Big/Small guys on Pontiac V8's - let 'em flaunt their "knowledge". Apparently, Pontiac made it so simple it's confusing. Couple points on the video: 421 was made through '66 and optional in full-size cars (Catalina, Bonneville, Grand Prix). There were Super Duty (VERY rare and expensive) and H.O versions made as well. Also, the 350 H.O. of '68-'69 is probably one of the most underrated Pontiac performance engines ever produced. It used the Ram Air III cam, heads, intake and carb and due to its lower reciprocating weight, was a much freer revving engine than the 400. It's downfall was a lack of promotion and timing - cubes were king when it was introduced. Had it come out around '71, things may have been very different. Another important fact often overlooked by non-Pontiac people - Pontiac V8's are NOT high-revving horsepower engines! They are low revving TORQUE engines. Pontiacs respond much better with relatively conservative cam selection and 3.90 or lower gears. I've gone 13.83 @ 102 mph in a 3,800 pound, 400-powered Trans Am with 3.23 gears.
Great info man. I'm a Pontiac guy myself, and I've had a couple of the engines you talked about, including a couple 301s and the lowly 265. It's true they were turds, but most Pontiac parts (including heads) would bolt up. Because of the shortened deck height, however, once new heads were on there was no intake in the world that would fit. If you want to build one, find a 400 from '67 to '73. The later ones went through some lightening and therefore lost a little strength. Great engine though. I have a 400 now and even stock with a 2bbl it still moves
Thank God! I’ve been trying to tell people this about the Pontiac block since I bought my first ‘68 Firebird. It was the 350 4bbl 4spd with the factory 3:90 posi (limited slip) rear. My buddy totaled a ‘70 Bonneville and I got the 455 4 bbl for $100. Along the way I picked up a tri-power setup from a GTO for $75 and guess what ? I bolted all this together, dropped it into the Firebird and it FLEW. Later rebuilt the engine switched the tranny to a turbo 400 and it would run 7 grand on the tach. I only sold it after twisting that 160 mph speedometer straight down. Ahh the memories I have of wrenching on that car. Thanks again , loved your info
Many thanks for doing this video. I'm an engineer and had a 1967 GTO when I was in school from 69 to 72. Unfortunately it overheated and blew up in 1973 and I had to find a replacement 400 for the car. It was difficult at the time because the crank shaft rear bearing for the Munci 4 speed I had was different than the automatic so I learned more than I wanted to know back then putting the engine back together. Today I have a restored Eldorado I take to car shows but can't tell you how many times I've had this discussion regarding the Pontiac block sizes especially with guys that have a 455. Many insist that the 389 that they put in the GTO in 1966 was a smaller block than the 400 for 67. I think in the future I'll take an IPad with me with the link to your video.
What a great video, I'm a huge Pontiac guy and I have a 301ci (blown from my TA) and i replaced it with a 1968 400 HO and this engine is ballsy as hell!. Many people refer to the Pontiac engine as an "Intermediate" block. I will say that the RAM AiR IV (if you can find one is a rare engine with many custom parts like the heads which are round port and the forged cranks which are 4 bolt mains along with other upgrades and they went like hell but super rare. I think they only made 580 or so. The 455 cu engines both the HO and later the Super Duty engines had relatively low compression 8.4:1 to meet new emissions laws but made gobs of torque and were some of the best high HP motors Pontiac made in the early 70's I'm sorry you had to deal with that knucklehead claiming they made a big block, he is obviously clueless.
Great Vid, and thanks for taking the time to make it! I will add this: Like Chevy, Pontiac made Small and Large journal Engines. People ask me I just say My Engine is a large Journal Pontiac Engine. I think, in an effort to put a Pontiac 455 Above a SBC, the "big Block" montra was expanded upon.. But maybe the Large and Small Journals is just too much for simple minds to grasp?? dunno.. just some thought. Keep up the good work!
I am glad you made this video. I am often in conversations with people that swear that they have a big block pontiac, or olds engine. It's like talking to a brick wall getting people to understand there there were no big block bop's. Thanks
Great video. Could ve mentioned 421, 428 and 455 crank journal diameter being 3.25" versus 3" for 400s and smaller as a dimensional change internally but keep up the good work.
You are absolutely correct about the Pontiac blocks. The 421 was produced from 1963-66. (1962 for racing) The 421 was an option to the 389 which was standard on the full size cars.
Great info! I always wondered why they looked so similar. Especially sense I've been on the lookout for a 455 to put into my 88 GMC 3500. This info really helped me out on making a decision, thanks!
By the way just in case you didn't know the size of the engine is cast into the side of the block under the head where the freeze plugs are. The year of the block is cast next to the distributor hole on the top back of the block. The horse power code is a two letter stamp on the front of the engine next to the timing cover on the passenger side. Just look up Pontiac engine codes or look here: www.wallaceracing.com/engine.htm or here: www.wallaceracing.com/enginesearch4.htm Hope you find what you need Shane. Best Wishes n Blessings. Keith Noneya
i wanna clean up my engine bay with a little shine, do you have any info on companies with air cleaner and valve cover kits in chrome for a 265 pontiac, or will any one fit from a 350 on up to a 455
"Firebird indeed came with a 250 cubic inch OHC inline six known today as the Pontiac "Cammer." The Cammer was the brainchild of John Z. DeLorean when he headed Pontiac's advanced engineering team in the early 1960s. DeLorean wanted to build a sports car powered by an advanced inline six, and he tasked engine designer Malcom McKeller with creating the motor." - Road & Track
Great video! Right on the Pontiac engine know how.., the Turbo 4.9 (301) did have a heavy duty crank in it, the standard L-37 four barrel, L-27 two barrel version had the weight reduced small counter weight crank. Weaker lower end.., you needed a manual trans to pull any power out if it. Thanks for the video!
good info yes no big and small blocks but we refer to them as big and small journal. Being 3.00" up to 400 and 3.25" for 421 428 and 455. Big journal engines had excessive friction drag so hot ticket is to turn a big journal crank down to 3.00" and fit into a small journal engine essentially stroking it. All rods are the same 326 to 455 but pistons varied
You are now better off getting a Butler performance stroker kit for the 400 3" main and stroking it. Pontiac magazine had a bit of a controversy over turning down the crank size of a 455 crank to fit the 3" main size.
I'm so glad you made this video. There are some ignorant people out there. The only thing i saw wrong with the video is the 455 actually has a 4.21 inch stroke, not a 4 inch stroke. I have a 455 and I love it! Pontiac's are torque monsters.
As cool as it would be to have a 455, the crank mains are bringing it down. A 400 with the bore and stroke on the small crank is the way to do it. Less friction, better oiling. Whats the 455 in?
Go to my page and check it out. Its in a 80 Trans Am. I understand the 3" main is a better performer under rpm. But my engine makes plenty of power below 5500. I have no issues. I utilize the long stroke to make gobs of torque.
78 was the last year. Around 8000, 1978 400 ci engines were mated to 4 speed standard transmissions and stock piled. These were installed in the 1979 Trans am .
@@ramairgto72 YOU understand grasshopper. You can wind up a small journal 400 four bolt main Pontiac ( AKA WW stamped Ram Air 4 ) with a aftermarket forged crank & rods waaaaaaay beyond any 455 with a forged crank & rods and the power is more than enough with a 400 to pull more horse power because the 400 cranks are so heavy that they really turn on AFTER 7,500rpm !. This is why the ultimate Pontiac motor of them ALL if you get rid of the factory cast crank & rods and use a forged crank & rods is the tunnel port Ram Air V 400 even out doing the 455/421 Super Dutys by alot. ( I never thought I would even find anyone but ME that knew this!)
This is an honest post I'm a ford man looking to buy a Pontiac because I always loved them and I knew this info and it's good to see a car guy speak of nothing but honest truth about honestly what he loves keep it up
The 428 and 455 blocks had larger crankshaft journals than the smaller cid engines. So I suppose a more accurate description would be small or large journal blocks.
@@maxxmasson4263 The 421 and 428 are less common than the 455 because they were only sold in the larger cars since GM had displacement limits on the popular intermediate cars which made up a lot of Pontiac sales in the 1960s. I used to see a lot of Tempest/Le Mans/GTO cars with the 326/389 or inline 6 engines but not nearly as many larger cars back in the day.
Thank you for the information on these kinds of engines. I am going to be working on a friends car. He is the same mind set as that viewer that thought of big block. I am not a Pontiac guy or even a Chevy guy but I will help him out. I am a ford guy building a 460 ford right now and I will be sending it out to the machine shop to get all ready. If you have any tips for me on that or maybe things to watch for from the machine shop that would be great. Thank you again for sharing.
I've bled Pontiac Blue for decades. And I've used my share of factory Hi-Po parts. But the aftermarket heads and blocks that are now available from multiple vendors allows for way more power with better reliability.
@@nemesisxrox6773 Vehicle Identification Number (VIN): The block VIN and the vehicle VIN were the same, but by late 1967 the block VIN was revised. It started out with a 2 (for Pontiac), the last digit of the year and a letter for the assembly plant followed by the last 6 digits of the vehicle VIN. It was located on the front of the block, on the passengers side, at the bottom near the timing cover.
I'm 67 years old and I knew about this Pontiac block thing before I ever got out of high school. I have always said that if you want a really dependable, strong, and capable engine that puts out a lot of horsepower without all kinds of mods to it, all you have to do is drop a Pontiac or Oldsmobile 455 engine into whatever you are running. I have always advocated the power of the 455. One of the best engines ever made. When I turned 18 years old I became a professional transfer driver for all of the dealerships in the southern region of the U.S. I drove just about everything you could imagine that ran on tires, sometimes short drives but sometimes many, many hundreds of miles all without stopping for anything except for fuel and pick up food on the go. It was one of the most enjoyable jobs I ever had and I was lucky to get the job. My biggest asset was to never open the trunk and keep my mouth shut if I had to open it and see what was in it. I also was never late and always on time. People would be amazed at what can be put in the trunk of a brand new Oldsmobile Ninety-Eight or Delta 88. The Buicks were about the same room size. Those 1970s model cars would really run through some miles and never strain those big 455s with the big ass quadrajet 4 barrels.
The only bad thing about the larger displacement Pontiac engines is that they have relatively short connecting rods, for the amount of crank stroke they have. Translated, cylinder wall side loading, and wear, which leads to oil burning after about 60,000 miles. Other than that, they are torque monsters. In fact a Pontiac regular production car had a Road and Track Magazine record for 0-60 mph. It was a 1963(?) full size Pontiac, with the 421 tri-power setup. The Pontiacs and the big Olds engines made lots of torque. Both were prone to burn oil as they built mileage, compared to others.
I have a Hot Rod Engine magazine from the 80s that I learned that from way back then. It did say the crank bores were bigger on some of the big cubic inch engines.
My 301 in my 81 Trans Am was a poor excuse for an engine. I ended up dropping a 455 in and it was a torque beast. 1981 was the first year they used a computer chip in the Trans Am and it was almost impossible to tune the car.
The Pontiac engines are in between the BBC and SBC size wise although the 455 has similar bore/stroke combo the casting number on the block is the best way to ID it
I know this is an older broadcast yet the numbers do not lie. This is how the GTO was born and was shuttled through not as a 326 but in reality a 389. Same block, same heads while the only difference was the bore and stroke which were still "Pontiac" design. After all the GTO was a sport trim option when it was first introduced. Of course the dealerships knew what was going on and loved it. There was a reason why the 1964 GTO was only available in a two coupe or two door hard top because the Le Mans convertible could not handle the torque of the 389. Engineering the same block and heads was brilliant!
Very cool video Sir. I learned in high school auto shop that Pontiac had a one size block and Olds did the same. Now in my 50s I've owned many 389s and later swapped to the 400 and 455s. Looking on the driver side of the block on the 70s casts had the size embossed in plain view. On the early casting meant learning the codes which could be a treasure hunt. I drive a '63 Bonneville with a '71 400 that has a '66 tripower. I went 400 to get away from the early 389 that had the old Jetaway trans. I put a Richmond 5 speed behind the 400 engine and it is a blast to drive. Thank You for the tutorial. Keep the young generation informed.
The 301 is a short deck so it the 265, it look like the block that you marked as a 350 have the larger mains which should be the other wat around . The 421,428 and 455 used 3.5 inch mains the rest used 3.0 inch. So there is a short deck , and a larger and small crnak bearring Pontiac.
The sd 455 was made in 73 and 74. There was no converter until 75. I had a 74 sd455 I bounght new. The cam was the same as a ram air 4... best cam ever in a pontiac motor. The problem was the exhaust system. The muffler was sideways between trunk and back seat. By removing the factory exhaust, adding hooker headers and thrush mufflers .. you gained 100 hp. I changed the gears from 308 to 372, added a b+m converter and shift kit and removed the plate from he hood scoop to make the ram air functional. The car would run 12.20 s all day long.
I had a 301... Yes it was a "bad" motor. Got it from a little old lady who just drove it to church, yet spun a lower rod bearing destroying the crank. put a short block in as a fix. 1978 Bonneville. :)
You are so right about the Pontiac engines. With that said, Pontiac engines are only ones that i know of that the intake manifolds and heads can be swapped without pulling the distributor every time.
I always love to show this video to people who firmly believe that Pontiac built a production big block engine, and watch as the steam begins to blast out of their ears. A long time ago, I did hear about Pontiac having dyno'ed a true big block that was in excess of 500cid, but when the "powers that be" at GM caught wind of it, they confiscated it, and destroyed it, all because they didn't want any Pontiac anything to outrun the golden child Corvette. I have never been able to find anything to confirm the 500+cid engine rumors, so if it is BS, I promise I won't get all twisted over it. GREAT VIDEO!!!!!!!!!
so this is probably the main reason I hear the term "large displacement" being used for Pontiac engines in all types of other videos and media on the subject? makes perfect sense now. Thanks for the info!
Wrong. Buick most certainly had a small block (215, 300, 340, 350 cubic inches, 4.24" bore spacing) and a big block (400, 430, 455 cubic inches, 4.75" bore spacing). These block families share almost zero parts in common. The Buick V6 was derived from the Buick small block V8.
+Myvintageiron7512 But the 301 is durable as hell its just not very strong, i had a buddy who had this ole le mans and it had 300,000 miles on it, it was no speed demon but it did last as long as you change the oil regularly.
+Pavielle Evans My dad drove a '77 Buick LeSabre with the 301 Pontiac engine ("Y" code in the VIN) which he then gave to me. It wasn't quick, but it was smooth as butter and very reliable.
The 301 had the same deck height as the 265... I blame blame these two junkers for the sbp/bbp confusion. Thank you for clearing this up, for those who just don't know.
I’m very late to the game here, but I was one of those Pontiac Big Block guys. I just picked up a 74 Grand Am with a 455 and now I know better. Thanks for setting me straight.
I remembered this at my firs job in 75 I worked for a Chevy dealer and I asked a seasoned mechanic that use to work for Pontiac and all he said was they are all the same there is no big block
well you have to admit that the block itself is kind of big lol love my Pontiac. they have one of the longest rods in a production car so rod stroke ration is excellent in bone stock configuration.
we also had a 80 Bonneville with a 301, with worn cam. so I had the idea to swap in a 69 olds 455, but never got done. I was only 15 and working alone. but the way the 455 moved the boat it was in. I bet it would really move the little( compared to the old olds) Bonneville. I wish I had it now. along with my 71 formula 400 firebird. I kick my self every time I think about how I gave it away basically. great video
100 percent right I'm 30 been restoring Pontiacs since I was 17 all motors are the same platform for the most part always loved the brand easy to interchange parts thanks for calling it out
Exactly. Unlike other manufacturers, Pontiac didn't need to design new blocks to get more power, They got it right the first time right out of the gate.
I've also a 78 ta with the original 400 block, but have a performer intake, edelbrock carburator, 2 1/4 dual stainless exhaust with two resonators and X-pipe. Runs great. Cheers from france!
Great video, and you are so right about Pontiac engines. With that said, Pontiac engines are the only ones that I know of where the intake manifolds and heads can be swapped without pulling the distributor.
Man you hit this out of the park. Thanks for the clean clear view of reality. That said I’ve owned both the 350 and the 400 Pontiac engine and there is a difference in performance but not much. But I did prefer the 400. Lol my mom had the 455 in her Grand Prix and it was an absolute torx monster. It was a 1970 all the bells and whistles. I owned the 72 Ventura II came with the 350 and yea I grenaded that one. Found the 400 with Chrome valve covers and rebuilt it. Massive difference. And yes it’s the same size block lol. As a young teenager at the time I called it a big block. Go figure but soon figured it out that all them blocks were in FACT the same size. No replacement for displacement. Shortly became my motto. I sold it like a dumpy when I was 20. Got it when I was 14 😁. Mis it greatly. That was 30+ years ago and not a day go’s by that I don’t think about it. Keep up the good work. I’ll be watching. ✌🏻
Thank you again for showing all of the bore and stroke sizes. That clears up the same arguments that I have been having with Idiots who claim that their 455 was a Big Block. I told them that it was only a matter of Bore and stroke that determined the motor size. I'll personally stick with a BBC motor over any other. You are one of the few people who really know what you are talking about. Thanks Pal...
I had a Pontiac big block 350 engine that I rebuilt at my high school back in 1979. I know he said that there has never been a big block Pontiac engine but when I removed the slant 6 out of my $150.00 1969 Firebird and then tried cramming in that 350 with headers in its place, I could have sworn that damned Pontiac 350 block doubled in size. The closer I got to the car the bigger that block got. I finally got it in there. I bought the 1969 Firebird from an ad in the paper (no internet back then). The man selling it was an airline pilot. It was listed in the paper for $150.00. Turns out that one of the exhaust valves had burned causing the Slant 6 not to run very good. When I went to pick up the car the owner (the pilot) was not there but his daughter and wife were there. I gave them a check for the $150.00, got the title and drove it home. Two weeks later I get a check in the mail from the pilot. In the letter, he apologizes for his wife and daughter, saying that they over-charged me for the car. Along with the letter was a check for $75.00. I was 16 then. When I was 18 wound-up getting rid of the car and regretted for over thirty years. Then I did some looking around and located the man that bought the car from me. He was going to restore it but never did. My 1969 Firebird has been sitting in a field about 100 miles away for the last 30 years. I told the man that I really wanted to restore it. The following week the man delivered my Firebird. He didn't charge me for the car or the haul. I checked archived vehicle registrations and the car is still under my name.
I really enjoy your information videos, I sure wish Id watched them before I started on a rebuild of a chevy 350. Im replacing a 305 in a 85 van, wanted more power. I bought a halfway done rebuild and had Cleggs Machine, a shop in Orem Utah do the milling put it together. They did a great job, Im just saying I have a shop and am starting to do some rebuilds outsourcing the machining and want to know what the inside is doing. I had a 396 in. a Pontiac bonneville and lived it, and didn't even cross my mind of the big or small block, makes sense, its all about bore and stroke and how they are accommodated . I look forward to all your information and will message when I get into the build deeper.
love this i was just about to write a comment about how there isn’t any differences for the most part. the only way pontiac could have a big block is if you race NHRA because anything over 400ci is considered a big block. great video!!
Good video - just one thing - as others have noted. The 455 stroke is 4.21" not 4.00". The 455 was oversquare - in that it's stroke was longer than the bore. It was the first Pontiac V8 to be built as an oversquare engine. This makes the 455 unique among the Pontiac engines, and also unlike the other similar 3.25" main journal engines, the 421 and 428 which were were both undersquare, with a 4" stroke and 4.094 and 4.121" bores respectively.
I actually had one of the OHC inline 6 engine , didn't realize what I had , good video , love pontiac , got a 1972 455 H.O. now in a 1980 smokey n bandit car with a 4 speed .
You are absolutely right about Pontiac engines how ever when the factory would run out of Pontiac engines they would substitute Chevrolet engines and transmissions. My parents bought a Catalina that had a small block Chevrolet engine. It was a bugger to get parts from our local independent parts store because they would look it up in their books. This might be the reason why people think that there are 2 different blocks. By the way it was a real pig. Very low performance. Another tip off that it was not a true Pontiac engine.
only ever owned one Pontiac engine that I worked on , it was a 400, and all I did to it was a valve job and install a high volume oil pump. also ported the exhaust side a bit to improve flow. but I had no idea that they used the same block on all their V8's It was in a big boat with just a 2 barrel and it ran quite good. thank you for the info.
People who argue and criticize about trivial things like this, need to get a life! You are correct about Pontiac motors! And YOU sound like a real expert on these things! I've learned a LOT about motors, and you explain things very well. Thanks! Keep up the good work!
Thank you for showing this video, I have the same problem with my Chevy, Ford, Mopar friends. Even my son who has just started to get interested in muscle cars refered to my 400 as a big block. I just laughed at him and said who told you Pontiac made big block and small blocks in 1969? He said he told a friend of his about the GTO 400 and his friend said, "Oh your dad has a big block Pontiac". I told him to tell his friend Pontiac made only one block size/weight but changed the bore and stroke. The is no small or big block Pontiac V8's just Pontiac V8. So after educating him he went and educated his friend. The closest thing to a Pontiac small block is either a six cylinder or a four cylinder that pontiac commissioned some shop in the 80 or 90's to combine into a V8. It had two distributors etc. It was probably the last ditch effort at a new true Pontiac V8 that could use off the shelf parts. I don't remember where I read it, but I think it was in HPP Magazine. By the way they were successful in the build. Thanks for the great post and keep em commin. Keith
the weak link on pontiacs was rod hardware failure so upgrade to arp or the like and oil pickups used to fall out into the pan. One reason they made such good power is they reverse cool and coolant flows to heads then block
My family's first car was a 1967 Pontiac Executive Safari Station Wagon with a 389 4 barrel(goat motor). The Poncho served our family very well through the years. My dad LOVED that car.
I love my 1971 GTO! Yes the engines are all the same size. But some people do believe there are Big and Small Block Pontiac Engines. Cool Video thanks.
To make it easy, journal size, bore and stroke make the difference in 95% of all Pontiac engines made. Good informational post. I would love one of the Ram Air V's, never seen one outside of youtube.
He's absolutely right about the 301 block. We had one in my 1977 Grand Prix - blew up before 63K miles and swapped in a 350. Then our 1979 Bonneville blew a motor and again, we threw in a 350. Finally, my sister's 1981 Firebird with the dreaded 301 - motor went out at 40K miles - what a piece of junk! We had much better luck with Chevy SB's. My 1980 Camaro had a 305 that my buddies and I built. My mom had a 1981 Monte Carlo with the 267 SB V8. Not powerful, but it ran well and we didn't have problems with it. A little different, modern Chevy - our 2008 Silverado with the 6.0L V8. Very thirsty, but strong and solid. And our 2007 GMC Sierra with two cylinders cut off 4.3L V-6. Not much power, but durable. Which GM motors, other than the 301 did we have problems with? How about the 1978 Buick 3.8L V-6 even fire. Motor blew up at 38K miles. Or the 1973 140 CI Vega motor. Sprung an oil leak, which became a huge leak. Car was wrecked in an accident with 28K miles - I guess we got lucky! Oh yeah, I almost forgot my 1983 Firebird with a 305 - the motor didn't blow up, but it didn't run very good and it got horrible fuel economy. Must've been built Monday morning or Friday afternoon. Great explanation of the different block sizes Pontiac uses. Change the title to 265 to 455 - the small displacement motor used in the Grand Prix (I know they used it in the Grand Prix).
My Dad had a couple of 64 Tempests, one with a 326. I got this talk when I was young because I remarked unknowingly that it was "probably the same" as a 327 Chevy. Hah. I remember one car had no front end and he got it home at night with a couple flashlights and magnets.
About 1992 I had a 2 door,69 Chevelle I put a 2bbl 283 in,had a 3 on the tree and 3.08 gears. A fella showed up with a trans am with that turbo 301. All he could say was how fast a turbo made his car. So we went to an empty street to race. My 283 ate that 301! We are talking car lengths at the finish line lol
Pontiac blocks are all the same size externally, bore and stroke sizes account for the difference in displacement. Technically they were medium blocks. Same thing goes for Buick and Oldsmobile. Some of the larger displacement Oldsmobile blocks did have a taller deck to accommodate the longer stroke, but still the same engine family as the smaller displacement engines. Ford, Chevy and Chrysler had true small block and big block engine families.
I get the whole thing about the "big block" and "small block" thing, and yeah they're pretty much the same sizes, but I wonder if they're considered "big" or "small" in an abstract sense due to the crank journals? A little research gave me some information that the 303/326/350/389/400 engines used a 3" main journal, while the 421/428/455 used a 3.25" crank journal. Though it might also be that people generally think that any engine over 400 cubic inches, no matter how it's designed, is a "big block". Even though it's not necessarily true, it's just "big displacement", as evident by the new trend of 400+ci aftermarket small block Chevrolet engines that directly break that conventional rule. I'm a big fan of Pontiac engines and Pontiac in general, and really want to try and build up some sort of big-journal Pontiac into a "sleeper" engine. At least to the guys who have no idea what the heck a Ram Air V top end looks like, especially when the heads, valve covers, and block are painted that blue color. I'm just having a hard time trying to figure out what exactly I want to swing with bottom end-wise. Thinkin' a decent 455 block with a stock bore size (if I can find one) and a smaller 4" stroke crank to make a "poser" .060-over 421-of-sorts (actually about 434ci).
Olds and Buick are the same way as Pontiac they all have the same block olds has one Buick etc they all share bell housing patterns bop. They called it
I'm currently building a Pontiac 400 for my Firebird. After it was bored (4.185) I had to stroke it to get the compression up. Bought a forged rotating assembly from Ohio Crank at 4.210 stroke (462CI) and with the 3" main journals. These engines have more than 10" of deck height which lends itself to a great deal of bore/stroke combos. And yes, I just shake my head when someone says they have a big block Pontiac.I have never been disappointed by any of my Pontiac builds.
For all we know he either had dish pistons or large chamber heads. Or maybe he wanted to run high octane or ethanol/methanol fuel. But regardless stroking an engine, all other things being equal, will always increase the CR.
I would have liked to be there when he argued with you about it. Funny stuff. I own and race a 1960 Pontiac Catalina. 497 ci blown engine that I built with my father who also raced a 60 Pontiac Ventura. 758hp and 1002fp torque. It runs 960's @ 136mph. Lots of fun. By this summer it will run in the high 8'S with new heads and pistons. Nice video
You are 100% correct, its neither a small block or a big block...just a Pontiac block. Maybe some people compare the Pontiac block to a Chevy or Ford small block and assume the "Big Block" theory for Pontiac. They'll learn sooner or later, Thanks for the videos
Besides the obvious ALL Pontiac V8's of that era are the same casting. Differences of each engine were cubic inch (bore, stroke, deck height.) There are casting differences of the V8 Pontiac. Engine mounting locations on the block, I.E. to remove a 400 Pontiac and stick a 428 back into its place will not just fall into the same foot print. Different engine mounts/fabrication will be required.
I agree the blocks are the same size externally , but i think you should have mentioned that the 455 HO block was reinforced in the lifter valley and other places that i can't for the life of me remember right now Lol , Love your stuff keep up the good work ! Oh yeah if you live in Canada you may remember the 400 American , It was a Pontiac 400 , but you were right about where it came from but so did the Chevy SB 400 ! Lol
Thank you for posting this. As a lifelong Pontiac person, it amazes me how many people who don't even own a Pontiac want to argue with me over the whole "Big Block" thing. For those utterly preoccupied with size, there's "Large Journal" 421-455 and "Small Journal" 400-down referring to the 3.25" or 3" crankshaft journal size. I've given up trying to convince the Big/Small guys on Pontiac V8's - let 'em flaunt their "knowledge". Apparently, Pontiac made it so simple it's confusing.
Couple points on the video: 421 was made through '66 and optional in full-size cars (Catalina, Bonneville, Grand Prix). There were Super Duty (VERY rare and expensive) and H.O versions made as well. Also, the 350 H.O. of '68-'69 is probably one of the most underrated Pontiac performance engines ever produced. It used the Ram Air III cam, heads, intake and carb and due to its lower reciprocating weight, was a much freer revving engine than the 400. It's downfall was a lack of promotion and timing - cubes were king when it was introduced. Had it come out around '71, things may have been very different. Another important fact often overlooked by non-Pontiac people - Pontiac V8's are NOT high-revving horsepower engines! They are low revving TORQUE engines. Pontiacs respond much better with relatively conservative cam selection and 3.90 or lower gears. I've gone 13.83 @ 102 mph in a 3,800 pound, 400-powered Trans Am with 3.23 gears.
The correct 455 Pontiac bore and stroke dimensions are 4.151" bore and 4.210" stroke. Great video!
Yes thank you that is correct . I was going to ad that fact also.
Great info man. I'm a Pontiac guy myself, and I've had a couple of the engines you talked about, including a couple 301s and the lowly 265. It's true they were turds, but most Pontiac parts (including heads) would bolt up. Because of the shortened deck height, however, once new heads were on there was no intake in the world that would fit. If you want to build one, find a 400 from '67 to '73. The later ones went through some lightening and therefore lost a little strength. Great engine though. I have a 400 now and even stock with a 2bbl it still moves
Thank God!
I’ve been trying to tell people this about the Pontiac block since I bought my first ‘68 Firebird. It was the 350 4bbl 4spd with the factory 3:90 posi (limited slip) rear. My buddy totaled a ‘70 Bonneville and I got the 455 4 bbl for $100. Along the way I picked up a tri-power setup from a GTO for $75 and guess what ? I bolted all this together, dropped it into the Firebird and it FLEW. Later rebuilt the engine switched the tranny to a turbo 400 and it would run 7 grand on the tach. I only sold it after twisting that 160 mph speedometer straight down.
Ahh the memories I have of wrenching on that car.
Thanks again , loved your info
Many thanks for doing this video. I'm an engineer and had a 1967 GTO when I was in school from 69 to 72. Unfortunately it overheated and blew up in 1973 and I had to find a replacement 400 for the car. It was difficult at the time because the crank shaft rear bearing for the Munci 4 speed I had was different than the automatic so I learned more than I wanted to know back then putting the engine back together. Today I have a restored Eldorado I take to car shows but can't tell you how many times I've had this discussion regarding the Pontiac block sizes especially with guys that have a 455. Many insist that the 389 that they put in the GTO in 1966 was a smaller block than the 400 for 67. I think in the future I'll take an IPad with me with the link to your video.
What a great video, I'm a huge Pontiac guy and I have a 301ci (blown from my TA) and i replaced it with a 1968 400 HO and this engine is ballsy as hell!. Many people refer to the Pontiac engine as an "Intermediate" block. I will say that the RAM AiR IV (if you can find one is a rare engine with many custom parts like the heads which are round port and the forged cranks which are 4 bolt mains along with other upgrades and they went like hell but super rare. I think they only made 580 or so. The 455 cu engines both the HO and later the Super Duty engines had relatively low compression 8.4:1 to meet new emissions laws but made gobs of torque and were some of the best high HP motors Pontiac made in the early 70's
I'm sorry you had to deal with that knucklehead claiming they made a big block, he is obviously clueless.
I'm a Pontiac fan/owner and you learned me a lot. Thanks for the video. Cheers from France
This is the first step I go to when I want to know something ! Best channel
Great Vid, and thanks for taking the time to make it! I will add this: Like Chevy, Pontiac made Small and Large journal Engines. People ask me I just say My Engine is a large Journal Pontiac Engine. I think, in an effort to put a Pontiac 455 Above a SBC, the "big Block" montra was expanded upon.. But maybe the Large and Small Journals is just too much for simple minds to grasp?? dunno.. just some thought. Keep up the good work!
Appreciate such a brief, yet well-detailed video.
God bless you #MakePontiacGreatAgain 🇺🇸
Your 100% tight. I'm 74 years old and a hard Cour PMD man from way back.
I am glad you made this video. I am often in conversations with people that swear that they have a big block pontiac, or olds engine. It's like talking to a brick wall getting people to understand there there were no big block bop's. Thanks
Excellent 👏🏻 well said!!!
Finally some one who knows what he’s talking about!
New subscriber👍🏻
Appreciate your well-detailed video. God bless you.
Great blog! It's encouraging to see a guy that knows what he is talking about, Thank you.
Thank you for this video,I've been saying this for years
Great video. Could ve mentioned 421, 428 and 455 crank journal diameter being 3.25" versus 3" for 400s and smaller as a dimensional change internally but keep up the good work.
hey how about doing one on Pontiac heads. .the good the bad...thanks.
Wallace racing has a nice list of them
KRE warp 6 ram air V heads the best of the best.
@@kukamungaphobia924 what do you base this on?
@@kukamungaphobia924smoking crack, everyone knows the big block 455 head is the best.
You are absolutely correct about the Pontiac blocks. The 421 was produced from 1963-66. (1962 for racing) The 421 was an option to the 389 which was standard on the full size cars.
Great info! I always wondered why they looked so similar. Especially sense I've been on the lookout for a 455 to put into my 88 GMC 3500. This info really helped me out on making a decision, thanks!
By the way just in case you didn't know the size of the engine is cast into the side of the block under the head where the freeze plugs are. The year of the block is cast next to the distributor hole on the top back of the block. The horse power code is a two letter stamp on the front of the engine next to the timing cover on the passenger side. Just look up Pontiac engine codes or look here: www.wallaceracing.com/engine.htm or here: www.wallaceracing.com/enginesearch4.htm
Hope you find what you need Shane. Best Wishes n Blessings. Keith Noneya
Yes pontiac made an overhead cam inline 6 way ahead of its time
two different versions, the standard OHC 6(2bbl) and the Sprint OHC 6 (4bbl and bigger cam).
i wanna clean up my engine bay with a little shine, do you have any info on companies with air cleaner and valve cover kits in chrome for a 265 pontiac, or will any one fit from a 350 on up to a 455
HMM Id look on ebay
"Firebird indeed came with a 250 cubic inch OHC inline six known today as the Pontiac "Cammer." The Cammer was the brainchild of John Z. DeLorean
when he headed Pontiac's advanced engineering team in the early 1960s.
DeLorean wanted to build a sports car powered by an advanced inline six, and he tasked engine designer Malcom McKeller with creating the motor." - Road & Track
That is correct I am planning on building one of them in a video sreies
I remember seeing a RAM AIR 5 303cid in a drag car that made over 650HP. It revved 10,000 RPM. Hell of a engine.
Thanks for the info. i love your channel!
Great video! Right on the Pontiac engine know how.., the Turbo 4.9 (301) did have a heavy duty crank in it, the standard L-37 four barrel, L-27 two barrel version had the weight reduced small counter weight crank. Weaker lower end.., you needed a manual trans to pull any power out if it. Thanks for the video!
good info yes no big and small blocks but we refer to them as big and small journal. Being 3.00" up to 400 and 3.25" for 421 428 and 455. Big journal engines had excessive friction drag so hot ticket is to turn a big journal crank down to 3.00" and fit into a small journal engine essentially stroking it. All rods are the same 326 to 455 but pistons varied
You are now better off getting a Butler performance stroker kit for the 400 3" main and stroking it. Pontiac magazine had a bit of a controversy over turning down the crank size of a 455 crank to fit the 3" main size.
I'm so glad you made this video. There are some ignorant people out there. The only thing i saw wrong with the video is the 455 actually has a 4.21 inch stroke, not a 4 inch stroke. I have a 455 and I love it! Pontiac's are torque monsters.
As cool as it would be to have a 455, the crank mains are bringing it down. A 400 with the bore and stroke on the small crank is the way to do it.
Less friction, better oiling.
Whats the 455 in?
Go to my page and check it out. Its in a 80 Trans Am. I understand the 3" main is a better performer under rpm. But my engine makes plenty of power below 5500. I have no issues. I utilize the long stroke to make gobs of torque.
Also the 400 was made until 79, not 78.
78 was the last year.
Around 8000, 1978 400 ci engines were mated to 4 speed standard transmissions and stock piled.
These were installed in the 1979 Trans am .
@@ramairgto72 YOU understand grasshopper. You can wind up a small journal 400 four bolt main Pontiac ( AKA WW stamped Ram Air 4 ) with a aftermarket forged crank & rods waaaaaaay beyond any 455 with a forged crank & rods and the power is more than enough with a 400 to pull more horse power because the 400 cranks are so heavy that they really turn on AFTER 7,500rpm !. This is why the ultimate Pontiac motor of them ALL if you get rid of the factory cast crank & rods and use a forged crank & rods is the tunnel port Ram Air V 400 even out doing the 455/421 Super Dutys by alot. ( I never thought I would even find anyone but ME that knew this!)
Thanks,I used to have a puny 301;but I loved it when I took long road trips,cruised great
This is an honest post I'm a ford man looking to buy a Pontiac because I always loved them and I knew this info and it's good to see a car guy speak of nothing but honest truth about honestly what he loves keep it up
The 428 and 455 blocks had larger crankshaft journals than the smaller cid engines. So I suppose a more accurate description would be small or large journal blocks.
Correct. Except you forgot the 421 had the large journal too.
I forgot about the 421. I guess because they're not as common.
And short or tall decks.
youre right I believe the 421 also had the 3.25 mains and the other blocks had the 3 inch journals
@@maxxmasson4263 The 421 and 428 are less common than the 455 because they were only sold in the larger cars since GM had displacement limits on the popular intermediate cars which made up a lot of Pontiac sales in the 1960s. I used to see a lot of Tempest/Le Mans/GTO cars with the 326/389 or inline 6 engines but not nearly as many larger cars back in the day.
Thank you for the information on these kinds of engines. I am going to be working on a friends car. He is the same mind set as that viewer that thought of big block. I am not a Pontiac guy or even a Chevy guy but I will help him out. I am a ford guy building a 460 ford right now and I will be sending it out to the machine shop to get all ready. If you have any tips for me on that or maybe things to watch for from the machine shop that would be great. Thank you again for sharing.
i never knew that fact about pontiac engines.thanks for the upload.
I've bled Pontiac Blue for decades. And I've used my share of factory Hi-Po parts. But the aftermarket heads and blocks that are now available from multiple vendors allows for way more power with better reliability.
... u may b a good source for info - did Pontiac stamp vin's on blocks ?
@@nemesisxrox6773 Vehicle Identification Number (VIN):
The block VIN and the vehicle VIN were the same, but by late 1967 the block VIN was revised. It started out with a 2 (for Pontiac), the last digit of the year and a letter for the assembly plant followed by the last 6 digits of the vehicle VIN. It was located on the front of the block, on the passengers side, at the bottom near the timing cover.
I'm 67 years old and I knew about this Pontiac block thing before I ever got out of high school. I have always said that if you want a really dependable, strong, and capable engine that puts out a lot of horsepower without all kinds of mods to it, all you have to do is drop a Pontiac or Oldsmobile 455 engine into whatever you are running. I have always advocated the power of the 455. One of the best engines ever made. When I turned 18 years old I became a professional transfer driver for all of the dealerships in the southern region of the U.S. I drove just about everything you could imagine that ran on tires, sometimes short drives but sometimes many, many hundreds of miles all without stopping for anything except for fuel and pick up food on the go. It was one of the most enjoyable jobs I ever had and I was lucky to get the job. My biggest asset was to never open the trunk and keep my mouth shut if I had to open it and see what was in it. I also was never late and always on time. People would be amazed at what can be put in the trunk of a brand new Oldsmobile Ninety-Eight or Delta 88. The Buicks were about the same room size. Those 1970s model cars would really run through some miles and never strain those big 455s with the big ass quadrajet 4 barrels.
That's when gm and their divisions had their own engines. The good old days.
The only bad thing about the larger displacement Pontiac engines is that they have relatively short connecting rods, for the amount of crank stroke they have. Translated, cylinder wall side loading, and wear, which leads to oil burning after about 60,000 miles. Other than that, they are torque monsters. In fact a Pontiac regular production car had a Road and Track Magazine record for 0-60 mph. It was a 1963(?) full size Pontiac, with the 421 tri-power setup. The Pontiacs and the big Olds engines made lots of torque. Both were prone to burn oil as they built mileage, compared to others.
that's interesting to know about the sideloading. are the 455's immune from that?
I have a Hot Rod Engine magazine from the 80s that I learned that from way back then. It did say the crank bores were bigger on some of the big cubic inch engines.
My 301 in my 81 Trans Am was a poor excuse for an engine. I ended up dropping a 455 in and it was a torque beast. 1981 was the first year they used a computer chip in the Trans Am and it was almost impossible to tune the car.
In a little lighter car (GP) the 301 wasnt as bad...3200lbs vs the TA 3600lbs
brian r on paper maybe but the 301 is just a poor performer wit weak internals
The Pontiac engines are in between the BBC and SBC size wise although the 455 has similar bore/stroke combo the casting number on the block is the best way to ID it
I know this is an older broadcast yet the numbers do not lie. This is how the GTO was born and was shuttled through not as a 326 but in reality a 389. Same block, same heads while the only difference was the bore and stroke which were still "Pontiac" design. After all the GTO was a sport trim option when it was first introduced. Of course the dealerships knew what was going on and loved it. There was a reason why the 1964 GTO was only available in a two coupe or two door hard top because the Le Mans convertible could not handle the torque of the 389. Engineering the same block and heads was brilliant!
Very cool video Sir. I learned in high school auto shop that Pontiac had a one size block and Olds did the same. Now in my 50s I've owned many 389s and later swapped to the 400 and 455s. Looking on the driver side of the block on the 70s casts had the size embossed in plain view. On the early casting meant learning the codes which could be a treasure hunt. I drive a '63 Bonneville with a '71 400 that has a '66 tripower. I went 400 to get away from the early 389 that had the old Jetaway trans. I put a Richmond 5 speed behind the 400 engine and it is a blast to drive. Thank You for the tutorial. Keep the young generation informed.
So my logic says that a 455 will fit into the same trans am as a 301, correct?
Yep..
The 301 is a short deck so it the 265, it look like the block that you marked as a 350 have the larger mains which should be the other wat around . The 421,428 and 455 used 3.5 inch mains the rest used 3.0 inch. So there is a short deck , and a larger and small crnak bearring Pontiac.
Yup
1973 SD455 engine probably has the most potential out of the Pontiacs. Just needs some compression and a big cam.
midnitesquirldog1 fr? I would like to hear more bout that
The SD was the best overall design but smog killed it, the 1970 455 HO was the best of all factory 455's because it was the only non smog year 455.
The sd 455 was made in 73 and 74. There was no converter until 75. I had a 74 sd455 I bounght new. The cam was the same as a ram air 4... best cam ever in a pontiac motor. The problem was the exhaust system. The muffler was sideways between trunk and back seat. By removing the factory exhaust, adding hooker headers and thrush mufflers .. you gained 100 hp. I changed the gears from 308 to 372, added a b+m converter and shift kit and removed the plate from he hood scoop to make the ram air functional. The car would run 12.20 s all day long.
I had a 301... Yes it was a "bad" motor. Got it from a little old lady who just drove it to church, yet spun a lower rod bearing destroying the crank. put a short block in as a fix. 1978 Bonneville. :)
You are so right about the Pontiac engines. With that said, Pontiac engines are only ones that i know of that the intake manifolds and heads can be swapped without pulling the distributor every time.
The stroke on the 455 is 4.21", you said 4.00".
The 301T block is stronger than the 301 naturally aspirated 301. There are some people in the 11s-12s look at the 301 garage forum. great vid.
I always love to show this video to people who firmly believe that Pontiac built a production big block engine, and watch as the steam begins to blast out of their ears. A long time ago, I did hear about Pontiac having dyno'ed a true big block that was in excess of 500cid, but when the "powers that be" at GM caught wind of it, they confiscated it, and destroyed it, all because they didn't want any Pontiac anything to outrun the golden child Corvette. I have never been able to find anything to confirm the 500+cid engine rumors, so if it is BS, I promise I won't get all twisted over it. GREAT VIDEO!!!!!!!!!
so this is probably the main reason I hear the term "large displacement" being used for Pontiac engines in all types of other videos and media on the subject? makes perfect sense now. Thanks for the info!
Olds and Buick did same gig a different way...no big or small
Wrong. Buick most certainly had a small block (215, 300, 340, 350 cubic inches, 4.24" bore spacing) and a big block (400, 430, 455 cubic inches, 4.75" bore spacing). These block families share almost zero parts in common. The Buick V6 was derived from the Buick small block V8.
The 301 Pontiac was a complete terd don't waste your time
my 301 runs pretty damn good
Lol your opinion but I'm not saying its better I'm just telling my 301 run pretty good that's all
+Myvintageiron7512 But the 301 is durable as hell its just not very strong, i had a buddy who had this ole le mans and it had 300,000 miles on it, it was no speed demon but it did last as long as you change the oil regularly.
Thank you jay bradley it's done the job so far so I have no complaints
+Pavielle Evans My dad drove a '77 Buick LeSabre with the 301 Pontiac engine ("Y" code in the VIN) which he then gave to me. It wasn't quick, but it was smooth as butter and very reliable.
Wow you cleared everything up in a very short time . Thank you very much .
The 301 had the same deck height as the 265... I blame blame these two junkers for the sbp/bbp confusion. Thank you for clearing this up, for those who just don't know.
i think your 455 specs are wrong.
I’m very late to the game here, but I was one of those Pontiac Big Block guys. I just picked up a 74 Grand Am with a 455 and now I know better. Thanks for setting me straight.
I remembered this at my firs job in 75 I worked for a Chevy dealer and I asked a seasoned mechanic that use to work for Pontiac and all he said was they are all the same there is no big block
well you have to admit that the block itself is kind of big lol love my Pontiac. they have one of the longest rods in a production car so rod stroke ration is excellent in bone stock configuration.
we also had a 80 Bonneville with a 301, with worn cam. so I had the idea to swap in a 69 olds 455, but never got done. I was only 15 and working alone. but the way the 455 moved the boat it was in. I bet it would really move the little( compared to the old olds) Bonneville. I wish I had it now. along with my 71 formula 400 firebird. I kick my self every time I think about how I gave it away basically. great video
Yea we all have that one car we regret getting rid of I had a 68 dodge coronet I sold for nothing had a floor shiftier and a 440 it's worth a mint now
100 percent right I'm 30 been restoring Pontiacs since I was 17 all motors are the same platform for the most part always loved the brand easy to interchange parts thanks for calling it out
Exactly. Unlike other manufacturers, Pontiac didn't need to design new blocks to get more power, They got it right the first time right out of the gate.
thanks for the info. Very helpful. Love my 78 t/a with the original 400
I've also a 78 ta with the original 400 block, but have a performer intake, edelbrock carburator, 2 1/4 dual stainless exhaust with two resonators and X-pipe. Runs great. Cheers from france!
Very good tutorial on this matter. I appreciate your efforts of explanation and proof of information.
Great video, and you are so right about Pontiac engines. With that said, Pontiac engines are the only ones that I know of where the intake manifolds and heads can be swapped without pulling the distributor.
Man you hit this out of the park. Thanks for the clean clear view of reality. That said I’ve owned both the 350 and the 400 Pontiac engine and there is a difference in performance but not much. But I did prefer the 400. Lol my mom had the 455 in her Grand Prix and it was an absolute torx monster. It was a 1970 all the bells and whistles. I owned the 72 Ventura II came with the 350 and yea I grenaded that one. Found the 400 with Chrome valve covers and rebuilt it. Massive difference. And yes it’s the same size block lol. As a young teenager at the time I called it a big block. Go figure but soon figured it out that all them blocks were in FACT the same size. No replacement for displacement. Shortly became my motto. I sold it like a dumpy when I was 20. Got it when I was 14 😁. Mis it greatly. That was 30+ years ago and not a day go’s by that I don’t think about it. Keep up the good work. I’ll be watching. ✌🏻
Thank you again for showing all of the bore and stroke sizes. That clears up the same arguments that I have been having with Idiots who claim that their 455 was a Big Block. I told them that it was only a matter of Bore and stroke that determined the motor size. I'll personally stick with a BBC motor over any other. You are one of the few people who really know what you are talking about. Thanks Pal...
I had a Pontiac big block 350 engine that I rebuilt at my high school back in 1979. I know he said that there has never been a big block Pontiac engine but when I removed the slant 6 out of my $150.00 1969 Firebird and then tried cramming in that 350 with headers in its place, I could have sworn that damned Pontiac 350 block doubled in size. The closer I got to the car the bigger that block got. I finally got it in there.
I bought the 1969 Firebird from an ad in the paper (no internet back then). The man selling it was an airline pilot. It was listed in the paper for $150.00. Turns out that one of the exhaust valves had burned causing the Slant 6 not to run very good. When I went to pick up the car the owner (the pilot) was not there but his daughter and wife were there. I gave them a check for the $150.00, got the title and drove it home. Two weeks later I get a check in the mail from the pilot. In the letter, he apologizes for his wife and daughter, saying that they over-charged me for the car. Along with the letter was a check for $75.00. I was 16 then. When I was 18 wound-up getting rid of the car and regretted for over thirty years. Then I did some looking around and located the man that bought the car from me. He was going to restore it but never did. My 1969 Firebird has been sitting in a field about 100 miles away for the last 30 years. I told the man that I really wanted to restore it. The following week the man delivered my Firebird. He didn't charge me for the car or the haul. I checked archived vehicle registrations and the car is still under my name.
Thank you! That has helped a great deal!
I really enjoy your information videos, I sure wish Id watched them before I started on a rebuild of a chevy 350. Im replacing a 305 in a 85 van, wanted more power. I bought a halfway done rebuild and had Cleggs Machine, a shop in Orem Utah do the milling put it together. They did a great job, Im just saying I have a shop and am starting to do some rebuilds outsourcing the machining and want to know what the inside is doing. I had a 396 in. a Pontiac bonneville and lived it, and didn't even cross my mind of the big or small block, makes sense, its all about bore and stroke and how they are accommodated . I look forward to all your information and will message when I get into the build deeper.
love this i was just about to write a comment about how there isn’t any differences for the most part. the only way pontiac could have a big block is if you race NHRA because anything over 400ci is considered a big block. great video!!
Good video - just one thing - as others have noted. The 455 stroke is 4.21" not 4.00". The 455 was oversquare - in that it's stroke was longer than the bore. It was the first Pontiac V8 to be built as an oversquare engine. This makes the 455 unique among the Pontiac engines, and also unlike the other similar 3.25" main journal engines, the 421 and 428 which were were both undersquare, with a 4" stroke and 4.094 and 4.121" bores respectively.
The only Pontiac engine I think that should have been added is the 366. Absolutely great video.
I actually had one of the OHC inline 6 engine , didn't realize what I had , good video , love pontiac , got a 1972 455 H.O. now in a 1980 smokey n bandit car with a 4 speed .
You are absolutely right about Pontiac engines how ever when the factory would run out of Pontiac engines they would substitute Chevrolet engines and transmissions. My parents bought a Catalina that had a small block Chevrolet engine. It was a bugger to get parts from our local independent parts store because they would look it up in their books. This might be the reason why people think that there are 2 different blocks. By the way it was a real pig. Very low performance. Another tip off that it was not a true Pontiac engine.
Have a 72' lemans! Great video man! 🤘🏻🤘🏻
only ever owned one Pontiac engine that I worked on , it was a 400, and all I did to it was a valve job and install a high volume oil pump. also ported the exhaust side a bit to improve flow. but I had no idea that they used the same block on all their V8's It was in a big boat with just a 2 barrel and it ran quite good. thank you for the info.
People who argue and criticize about trivial things like this, need to get a life! You are correct about Pontiac motors! And YOU sound like a real expert on these things! I've learned a LOT about motors, and you explain things very well. Thanks! Keep up the good work!
Thank you for showing this video, I have the same problem with my Chevy, Ford, Mopar friends. Even my son who has just started to get interested in muscle cars refered to my 400 as a big block. I just laughed at him and said who told you Pontiac made big block and small blocks in 1969? He said he told a friend of his about the GTO 400 and his friend said, "Oh your dad has a big block Pontiac". I told him to tell his friend Pontiac made only one block size/weight but changed the bore and stroke. The is no small or big block Pontiac V8's just Pontiac V8. So after educating him he went and educated his friend. The closest thing to a Pontiac small block is either a six cylinder or a four cylinder that pontiac commissioned some shop in the 80 or 90's to combine into a V8. It had two distributors etc. It was probably the last ditch effort at a new true Pontiac V8 that could use off the shelf parts. I don't remember where I read it, but I think it was in HPP Magazine. By the way they were successful in the build.
Thanks for the great post and keep em commin. Keith
the weak link on pontiacs was rod hardware failure so upgrade to arp or the like and oil pickups used to fall out into the pan. One reason they made such good power is they reverse cool and coolant flows to heads then block
My family's first car was a 1967 Pontiac Executive Safari Station Wagon with a 389 4 barrel(goat motor). The Poncho served our family very well through the years. My dad LOVED that car.
thanks 4 the video I didn't know that they were the same size block.good info
I love my 1971 GTO! Yes the engines are all the same size. But some people do believe there are Big and Small Block Pontiac Engines. Cool Video thanks.
To make it easy, journal size, bore and stroke make the difference in 95% of all Pontiac engines made. Good informational post. I would love one of the Ram Air V's, never seen one outside of youtube.
Sir you are absolutely right about pontiac engine's I have a. 030 400 in a 79 transam runs awesome
Very good video, i love quality education. Thank you for sharing .
He's absolutely right about the 301 block. We had one in my 1977 Grand Prix - blew up before 63K miles and swapped in a 350. Then our 1979 Bonneville blew a motor and again, we threw in a 350. Finally, my sister's 1981 Firebird with the dreaded 301 - motor went out at 40K miles - what a piece of junk!
We had much better luck with Chevy SB's. My 1980 Camaro had a 305 that my buddies and I built. My mom had a 1981 Monte Carlo with the 267 SB V8. Not powerful, but it ran well and we didn't have problems with it. A little different, modern Chevy - our 2008 Silverado with the 6.0L V8. Very thirsty, but strong and solid. And our 2007 GMC Sierra with two cylinders cut off 4.3L V-6. Not much power, but durable.
Which GM motors, other than the 301 did we have problems with? How about the 1978 Buick 3.8L V-6 even fire. Motor blew up at 38K miles. Or the 1973 140 CI Vega motor. Sprung an oil leak, which became a huge leak. Car was wrecked in an accident with 28K miles - I guess we got lucky! Oh yeah, I almost forgot my 1983 Firebird with a 305 - the motor didn't blow up, but it didn't run very good and it got horrible fuel economy. Must've been built Monday morning or Friday afternoon.
Great explanation of the different block sizes Pontiac uses. Change the title to 265 to 455 - the small displacement motor used in the Grand Prix (I know they used it in the Grand Prix).
Great video lotta information thank you so much my friend
My Dad had a couple of 64 Tempests, one with a 326. I got this talk when I was young because I remarked unknowingly that it was "probably the same" as a 327 Chevy. Hah. I remember one car had no front end and he got it home at night with a couple flashlights and magnets.
Great video, thank you.
About 1992 I had a 2 door,69 Chevelle I put a 2bbl 283 in,had a 3 on the tree and 3.08 gears. A fella showed up with a trans am with that turbo 301. All he could say was how fast a turbo made his car.
So we went to an empty street to race. My 283 ate that 301! We are talking car lengths at the finish line lol
great info ,,,,i hope you can demonstrate next Pontiac approach on their approach in abstracting different power from same block
Very good information !!
Pontiac blocks are all the same size externally, bore and stroke sizes account for the difference in displacement. Technically they were medium blocks. Same thing goes for Buick and Oldsmobile. Some of the larger displacement Oldsmobile blocks did have a taller deck to accommodate the longer stroke, but still the same engine family as the smaller displacement engines. Ford, Chevy and Chrysler had true small block and big block engine families.
I get the whole thing about the "big block" and "small block" thing, and yeah they're pretty much the same sizes, but I wonder if they're considered "big" or "small" in an abstract sense due to the crank journals? A little research gave me some information that the 303/326/350/389/400 engines used a 3" main journal, while the 421/428/455 used a 3.25" crank journal.
Though it might also be that people generally think that any engine over 400 cubic inches, no matter how it's designed, is a "big block". Even though it's not necessarily true, it's just "big displacement", as evident by the new trend of 400+ci aftermarket small block Chevrolet engines that directly break that conventional rule. I'm a big fan of Pontiac engines and Pontiac in general, and really want to try and build up some sort of big-journal Pontiac into a "sleeper" engine. At least to the guys who have no idea what the heck a Ram Air V top end looks like, especially when the heads, valve covers, and block are painted that blue color. I'm just having a hard time trying to figure out what exactly I want to swing with bottom end-wise. Thinkin' a decent 455 block with a stock bore size (if I can find one) and a smaller 4" stroke crank to make a "poser" .060-over 421-of-sorts (actually about 434ci).
Nope. Way too much thought, simple answer, block size, nothing internal makes it big or small in titles.
Thanks for a great video. I would like to see the same information about the Oldsmobile and Buick 350s and 455s.
Olds and Buick are the same way as Pontiac they all have the same block olds has one Buick etc they all share bell housing patterns bop. They called it
I'm currently building a Pontiac 400 for my Firebird. After it was bored (4.185) I had to stroke it to get the compression up. Bought a forged rotating assembly from Ohio Crank at 4.210 stroke (462CI) and with the 3" main journals. These engines have more than 10" of deck height which lends itself to a great deal of bore/stroke combos. And yes, I just shake my head when someone says they have a big block Pontiac.I have never been disappointed by any of my Pontiac builds.
no doubt about they run very strong
You don't stroke an engine to get the compression up.
For all we know he either had dish pistons or large chamber heads. Or maybe he wanted to run high octane or ethanol/methanol fuel. But regardless stroking an engine, all other things being equal, will always increase the CR.
Great job explaining, AMC did the same exact thing (every gen 2 block is identical out side)
I would have liked to be there when he argued with you about it. Funny stuff. I own and race a 1960 Pontiac Catalina. 497 ci blown engine that I built with my father who also raced a 60 Pontiac Ventura. 758hp and 1002fp torque. It runs 960's @ 136mph. Lots of fun. By this summer it will run in the high 8'S with new heads and pistons. Nice video
Yep Pontiac's are all the same block no BB or SB just a Pontiac
You are 100% correct, its neither a small block or a big block...just a Pontiac block. Maybe some people compare the Pontiac block to a Chevy or Ford small block and assume the "Big Block" theory for Pontiac. They'll learn sooner or later, Thanks for the videos
Besides the obvious ALL Pontiac V8's of that era are the same casting. Differences of each engine were cubic inch (bore, stroke, deck height.) There are casting differences of the V8 Pontiac. Engine mounting locations on the block, I.E. to remove a 400 Pontiac and stick a 428 back into its place will not just fall into the same foot print. Different engine mounts/fabrication will be required.
I agree the blocks are the same size externally , but i think you should have mentioned that the 455 HO block was reinforced in the lifter valley and other places that i can't for the life of me remember right now Lol , Love your stuff keep up the good work ! Oh yeah if you live in Canada you may remember the 400 American , It was a Pontiac 400 , but you were right about where it came from but so did the Chevy SB 400 ! Lol
The only production 455 with reinforced lifter galley was the 455 SUPER Duty.
Robert Eiler yes I just looked it up , SD IT IS !
This guy blows me away. Awesome.
This guy needs to do his home work on Pontiacs.