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305 Vortec Heads vs 350 Vortec Heads (Flow Data)
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- เผยแพร่เมื่อ 22 มี.ค. 2021
- Whats the difference between 305 vortec heads and 350 vortecs? This video should answer your questions and give you some real flow numbers
Plus a little bit of mild porting!
Maybe we should build a 355 Sbc with 305 vortec heads? Comment below!
305 Vortec heads:
520 or 059 casting
1.84 intake valve
1.5 Exhaust
350 Vortecs
906 or 062 casting
1.94 intake valve
1.5 Exhaust
My 059s were 224 cfm out of the box and close to 250 when ported with a 1.94/1.6 valve package. They respond well to bigger valves and a little chamber deshrouding. I did not touch the swirl ramp other than to blend it in a little more smoothly. Stock they still outflow a 2.02 camel hump.
My butt flows more air than a 305 head
I wanted a set of the 305 Vortec heads for a little 307 I had but traded the engine before that happened. Now I want that 307 back! Lol
Thank you for doing this. As an old hot rodder who still likes to build hot little 283s, you have my full attention. I have one fresh 30 over short block waiting for heads, and a second block going 40 over with a really nice rotating assy, so head choices need to be made.
Having said that, I see no reason to use 305 vortec heads on a 355, the 350 vortec chamber is worth too much power to give up just for the compression gain of the 305 heads. On a 355 there are better ways to get that bit of compression ratio back with piston choice ( and I mean the right flat top brand here), head gasket choice, and a bit of block decking.
For a smaller bore engine, though........you've got some good info here.
How do you build a 283. Did Chevy make engine smaller than 305 or did you just chop one up and modify it.
@@gtgodbear6320 Chevy built the 283 from 1957 to 1967. They are 3.875" bore and 3.000" stroke, and were available in full size cars and pickups during this time as well as Corvette 57-61, Chevelle 64-67, Nova 63-67
@@deuceman32 I think I just found my new favorite engine. I'm a huge fan of small displacement. Have you ever modernized one with fuel injection and electronic distributor/ ECU, turbocharged, and all the other Automotive words I have no idea what I'm talking about?
My oldest brother ha a 74 camaro stick shift, he use to do a bit of racing in. He said the fastest that car did was with a 283 and some old NASCAR cam
besides that you can fill in the combustion chamber and reshape it anyway.
That's kind of crazy 305 Chevy heads with TBI style Chevy headed combustion Chambers with Vortec intake manifold bolt patterns that would be cool to see an engine build with that heads on a dyno
Wow finally a video about the 305 Vortec Heads, thank you very much for this!
My 92 Camaro RS 305 TBI is getting this upgrade with a pair of 059s and a Edelbrock 7516 intake and I was looking for info like this.
Will keep you all posted when finished (Budget is tight nowadays).
I have built 520 heads for a 287 with a .525 lift cam exhaust porting, minor intake porting(leave the tiny ramp alone). These heads are 165cc intake, 70cc exhaust and ours had 59 cc chambers. It made that little mouse absolutely scream, had RPM air gap, 600 cfm Holley, 1 5/8 headers and a recurved HEI. Rev’ed easily to 7200, it was absolute music!
Super cool combo man!
I have a 97 305 Vortec truck with 300,000+ miles and it runs very strong and gets super mileage. Super awesome motor 👌.
Àß1spw pwpw is ² 2
Unless you're installing a larger cam without pulling the heads I think it's far easier to cut the tops of the guides. It only takes about 5 minutes with the proper cutter and a cordless drill, at that point you can run whatever springs and retainers you want without worrying about them hitting the seals or the tops of the guides.
Thank you for the video! The 305 vortec combustion chamber is almost the same as the 350 vortec, it just doesn't have the point that turns it into the heart shape, and that is fine, since the 350 heart shape point actually shrouds the exhaust valve flow out of the chamber. The 305 vortec chamber is nothing like a swirlport chamber for those that only see the lack of heart shape
So what do you think the purpose of the point is ? i look at it and i think there's a reason they put it there ....
@@luckyPiston 1 reason I can think of is to make the 350 chamber smaller cc for ~9:1 compression with the larger bore & stroke of 350.
@@archivegarage7638 K, how about if it was there to split the flame front traveling across the top of the chamber away from the spark plug ? by the time the piston is reaching TDC and quenching vapor into the flame front for ignition you could have a pretty interesting looking burn pattern ? a twin vortec ?
@@luckyPiston you're exactly right on the design and reasons why. The heart shaped chamber has a more efficient flame front, and is less prone to detonation.
I seen a video about Ford's racing with Glidden and Elliott's domination of the mid 80s. Both used Cleveland base design head' but both welded up the wedge shape chamber and machined heart shaped chambers back in. Everyone else was still running a wedge design.
@@kevind3185 Yeah i was thinking to fully optimize that feature with the 350 vortec head, go with flat tops or a D-dish so the piston mirrors the head, i have a 383 Vortec with D-dish KB pistons 9.75:1 compression and i run 87 octane on a regular basis, gets pretty decent gas mileage too so must be doing something right !
Having spent half of last night reviewing your previous videos I would be very interested in seeing what a 1.94 intake & a 1.60 exghaust on t 305 heads will show. And thank you for this. Ive had a hard time finding much info that would heĺp my problem and am danged glad I stumbled across your site. Im in CA. And t smog restrictions are a real problem. Without getting to deep, the best I think I could do ( so far..) is to use an 'aproved' RV cam to clear t test & then use 1.6 rockers for more lift. I cant even install t headers Ive bought OR dual exghaust until I can get my ass out of hear, that would be illegal in my '86 van. Thanx again.
I'm glad you put this info out it helps my decision. i have an el camimo with a 305 in it, I think putting my 305 vortec heads would help out in the power department a little.
it should gain power on the whole curve, I would think. do you think its possible that there would be a 15 horse gain? im gonna keep the stock cam in it.
i would love to see what some 1.94 valves woukd do on these. a valve job, some bowl work, and maybe a little short turn work would be interesting too.
I got a vortec 305 in my '96 and it run surprisingly well to have a 3.08 gear.
Yeah they work better than most older stock 350s thats for sure
Thank you it is great truly informative TH-cam Channel good things are coming your way dude
Appreciate all the info you do for us but love to see you do a set of peanut Port heads for a 454
The Combustion Chamber on the 305 Head is the biggest issue.. It's basically a old school wedge design vs a Modern Heart Shape. If everything was the same other then combustion chamber the heart shaped head will make more power.
Yeah totally agreee. The 305s vortecs has a very similar chamber to a tbi head. Flow is decent and compared to pre vortec heads its actually not bad
@@cuttersperformance the difference between the combustion chambers happens when both valves are shut and the spark plug fires, a Heart shaped combustion chamber makes a more efficient flame front then a wedge design.
good vid. good to know if I ever wanted to refresh a 305 but clearly buy 350 vortecs if youre touching a 350 and don't bother with these
Did you ever experiment more with porting on this head? Be curious what it would be capable of. Charles Servedio has been working on a 193 casting swirl port and has gotten over 300 cfm out of it 😮
I snagged a L31 from late 90s yukon from LQK and plan to use the 062 vortec heads with LS lifters and ls3/6 beehives as i have many used sets laying around from build LS engines. I got the offset valve locks and such. Motor is to upgrade an 86 Vette with a locked up L98. I also have a brand new zz4 cam that I'm debating to use over a low mileage cam from a 97 LT1 from an f-car. I'm thinking more using the LT1 cam with just LS1 beehives which are good to .520 lift. Also will be keeping it TPI fuel injected. And since I'm using the tpi system (and yes lower base from a 89 L98), I know the zz4 cam will not breathe in higher rpms like it is able to if was in an LT1 or a dual plane/carb w/ headers set-up.. But I also have a set of 113 L98 heads that were 'built' from what looks like a long time ago. And since I'm not sure how long (after getting the car running again) I plan to keep it, I don't want to use the 113 heads as we all know ate getting hard to find. Especially, since I snagged them up for just $200 that came with nice cast alum tall valve covers and aftermarket parts and hardened pushrods even. I do plan to port the 062 heads regardless. I do a lot of LS heads. But never did any sbc gen.1 or 2's. So I am learning some from another guy. But I am very eager to see final numbers. As I have an ole 88 K1500 with the GM 350 h.o. crate in it and she hauls azzzzz. With the 33x12.5x15 mudrovers on her, she spanks 4.6 poopstangs all day!!! And its the 4spd with low granny too. Its been a good 15 years since I built anything non-LS and am getting very eager! Looking forward to more vortec info! Thx for making this video!
I would like to get the part numbers for the the valve spring upgrade as well as the part numbers for the locks and retainers and I'm curious if they will be ok with a Crower 280 hydraulic flat tappet cam on a .40 over 350 please let me know what you think thanks for all your info
I purchased the CIFIC marine 059 replacement heads bare. Seems good quality.
Those if you look closely may have stellite exhaust seat inserts and 3/8" guides on the exhausts for HD marine use.
I came across a set of marine 217's that were set up like that so they may do the 059's that same way too , worth a check so you get the right exh v/v's
I like to see. Stock. 350 v. Up agents ported three angel 2.02 ..1.60. like 550 lift. FLAT top PISTONS. No OUTHER change. On the dino. Then in the car. I want to do that on my 4.3 but I need another set of stock heads..... And on both sets my factory valve job was junk. Like 10 those run out on the EX. LEAKED LIKE A SIVE. I WANTED TO BOLT THEM ON STOCK. SO NOW I HAVE TWO SET'S I F. WITH. DO TO THE RONA. AND GM. SHITTY WORK. THANK YOU FOR YOUR HARD WORK. PORTING CAST IRON HEADS SUCKS. NOT TO FORGET 125 THO. SEAT WITH. ON EX. JUNK.
Thank you for the data!
I was really surprised by the lack of heart shaped chamber. Thanks
Yeah kinda weird that they did that
@@cuttersperformance now I'm wondering if the 4.3 V6 vortec head has the chamber or not,lol.
Seems like a great bolt on upgrade for the dreaded TBI swirl port heads for some of us that have 305s. I’m curious on how they compare to the older 416/601 castings
601s are actually pretty good heads. they have the 53cc chambers so the valves are pretty shrouded. you take the chamber wall out to your cylinder bore and they really wake up. the 601s were the only heads Chevy ever used a bowl hog on to open up the runners from the factory. you clean up the bowl and deshrod the valves they will flow atleast 215 cfm and over 225cfm with a 5 angle valve job and the factory 1.84 valves backfaced. ive gotten factory vortec flow numbers (230ish) out of them with a little work.
@@konnerkramer329 wow thank you. I was not aware of that. I’m acquiring a 3rd gen firebird with that tbi 305 and I’m looking for more go without removing the block - so heads cam and intake will be changed. If I can find a good clean set of the 601s at a good price I would surely consider that option.
@@michaelgrasso4553 the last 305 build i did for someone was a budget build just like that. it was in a 86 c10 with a factory 601 headed 305. i left the engine in the truck while doing it. i first started by measuring how how in the hole the pistons were to setup the quench right. the were .020 in the hole so i used a .021 steel shim gasket. ported the heads as mentioned above. then took an edelbrock performer rpm intake and mached them to a felpro gaskets i think it ended up being a 1206 maybe a 1205. then i opened the intake runners on the heads up to the gasket and smoothed the pushrod wall. i used a budget summit racing cam. it was a 218/218 .450 lift with a 106 LSA. and a 650cfm holley DP. this combustion ran extremely well from 2500-6500 rpm and pulled very hard for a 305 in a full size truck. with a stock stall and 3:73 gears the full size full weight truck would give 2 valve mustangs a run foe their money. but what impressed me the most is that little 305 sounded like a fucking bracket car with that tight 106 lsa with the decent size cam for the 305. it probably made a conservative 300hp and 350tq but sounded like a 700hp 383. if you're curious about the build i would be happy to give you some advice and tips to help or if you want the videos of the truck i can send them to you
@@konnerkramer329 that sounds great, thank you! Im pretty sure that 305 tbi’s in the cars were set up for roller cams and I would probably want to stay with the roller lifters. I would love to know the details of your build and if you have any pics or video you can send me links to mgrasso@eseny.com
@@konnerkramer329 Thanks for posting the info on the 601's. As a "283 guy", the 1.84 intakes and 53cc chambers are golden for me, plus my collections of manifolds and valve covers are drop on's.
Try the LM7 valves. 1.9/1.55 with 8mm stems. Possibly 40°seats on the exhaust for a single pattern cam for more low speed torque. You could use stock LS guides or upgrade to bronze.
I would like to try LS valves in a vortec, something I haven't tried
@@cuttersperformanceDavid Vizard is looking to install LS valves in a pair of 318 heads for the Mission Impossible project. They are about 20g lighter each. Then if you have a 1.8" installed height, LS beehive springs, retainers and locks can be used for more weight reduction.
Hi from UK, liking the content. I'm stripping a 305 in the workshop as we speak, it's from a boat all original, but I'm sure came with mercruiser vortec heads, I'm curious about flow figures so I can pick a good head, I have a quadrijet and points ignition to put on it, all the things other people avoid, always had good results with points ignition, sorting ignition advance with springs and weights is the key!
Sorry pick a cam!
could you test the 350 tbi swirl port heads? curious to see the difference between 305 swirl port heads and 350 swirl port heads. im suprised removing the ramp didnt make much of a difference
Yeah I will try to get a set of swirl ports. I was alway surprised about the ramp being removed not changing much
We have to remember that flow is just one component of making power, and is doing so from a volumetric efficiency stand point (more air/fuel in and out). Factors like swirl and quench are components of combustion efficiency (getting it all lit and burnt fast without wrecking parts), a different way to make power (or fuel economy, or cleaner exhaust). So removing the ramp did little to change flow but would it change power output? We don't know.
@@deuceman32 thats exactly it! Only a dyno can tell that tale
@@cuttersperformance its been done before and the ramp, well its actually a block near the spark plug on the 882 heads on the 350 and 400 they say not to take out so its really exacting how and what should be done with it a block or a ramp in a head a very specific way. And definitely fill the crossover passage hole. i mean it is literally a hole in the center 4 cylinders only from the chamber to the other side through the manifold. That is crazy, a big hole right behind the chamber at the exhaust valve i guess..
Thank you for the last post, it does answer my interest in vortex heads 4 t 305 question. Regarding trying 305 heads on a 350, or larger block, I'm more curious about what you said of a 327. What about aftermarket pistons w/305 bore and a 327 crank. Is that even possible...?
Anyone have info on these 14011034. My friend quit racing years ago and gave me these fully ported/polished 2.055 intake valves girdles and screw in studs I know his car ran in the 10s with these heads on a 406 sbc and nitrous
Think they are gm performance phase 2 heads. Excellent heads!
Where they all flowed on a 4" bore, or the 305's flowed on a 3.736" like the 305 uses?
I would love to see what the swirl port ramp actually does to airflow. The obvious answer is that "It causes it to swirl," but I don't think it's that simple. Normal chevy and vortec chevy heads bias the intake flow to the outside of the port (to the cylinder wall side) and generate quite a bit of swirl because of that, the swirl port ramps are on the other side and almost block the flow on that side, I'm surprised that they didn't end the ramp sooner or later, either not blocking as much flow, or forcing it all to go around the outside side. I am impressed/surprised that you showed that the ramp didn't seem to hurt flow, I'm wondering if that would still be true with 1.94 or 2.02 valves. If it was you'd get some of the "heart-shaped" chambers back if you cut them for the larger valves, kind of like cutting old 602 casting 305 heads for larger valves, where you end up with a tiny (roughly 54cc) heart-shaped chamber.
I have experimented some with the swirl port heads and found that the swirl makes more power than the added flow you got from cutting the ramps down, so porting those you wanted to leave the ramps and just clean the rest up. You ended up with a low to midrange torque monster, perfect for a truck.
I suspect that a set of properly worked 305 vortecs with oversize valves would be a magic combination of power and MPG for a heavier vehicle.
if want to see a weird hybrid of design/thought process, check out some LT1 iron and LT1 aluminum heads. They have some qualities of traditional SBC heads, vortec heads, fastburn heads... and the iron are different than the aluminum. I'm running a set of LT1 aluminum heads on a 305 that are heavily worked (they flow almost 260 on the small 305 bore) and modified to work on the SBC with a victor jr converted to fuel injection. You'd never guess the 305 was a 305.
Swirl port and swirl bore are two different things, i don't think we have air flowing from the port to the bore like a corkscrew, i think the design is primarily promating flow into the center of the bore which leads to more efficient burn as the mixture is filling the cylinder in a more uniform way.
The mixture hitting the backside of the ski ramp is being deflicted down and is helping to turn air on the short side past the valve, there is a convergence that dumps mixture more down into the bore center instead of a non swirl port being more towards the cylinder wall in front of the exhaust valve.
I've been waiting for this, still trying to decide heads for my engine. I've heard the 059 casting is slightly better than the 520 castings, not sure if this is the case? Maybe something to look at in the future, or any 305 vortec head video would be fun in my book! Fun to see actual numbers produced vs what has been hearsay.
Yeah I've heard people say they flow abit better but I will have to get a set to verify that
I'll be anxiously waiting for sure!
WOW! I'm building a 305 and have a set of 416 heads and a set of 601 heads. I'm 72 years old and used to build engines 50 years ago but know nothing about vortec heads.
What should I do???
Vortecs will put proform just about any production sbc head! But it will depend on how much power you want to make
GM performance parts has that tbi intake for vortec heads, makes me wonder if this head and intake combo was going to go on say 95 trucks which is such an oddball truck anyway but they decided to wait a year and they had a better head for L31 350's. After all the 305 L30 head is a TBI/TPI head done correctly with the same good exhaust flow of the TBI head but better than TPI head intake flow.
I'm curious if velocity was changed.
I think 300 to 400 is a sweet spot for American V8s
Considering putting a set of 305 Vortec heads on a stock SBC 400 bottom end with stock pistons. Any advice/input on that? Quench area and head gasket selection?
1.90 x 1.56 seems to work well unschroud chambers seem to work well put them on a .040 bore 283 .
Any more info on that motor? I have a 283 in my garage, numbers say came out of 66 Deuce. Kind of want to build it put it in a 3rd gen F body or S10.
I tried, even listened on some of your other video introductions and it all sounds like Pown in the shop?I don't know, maybe that's your name? No offense, that's what it sounds like with my old ears.
Anyway if you can it would be very cool if you could measure the unported port volume on the 350 and 305 heads? That would be some great info to know.
The lesser the port volume a head has the easier time a smaller cid engine or a longer rod ratio shorter stroke engine has drawing in air flow.
Trying to decide which Vortec heads to use, 062 or 059(I have a set of each)for my sbc 400 block with a sbc 307 crank with 6.250" rods that will be a 355.
On one hand, the 305 will make it easier to get the compression up. But on the other hand, the 350 heads have the better swirl promoting chambers.
But maybe thats why that swirl is under the valve?(to make up for the older style chamber?)
Decisions decisions. 🤔 Thanks in advance.
Sorry about that but its Pat haha "Pat out in the shop"
I will have to check my note to see if I measured the intake runner on the 305 heads. I pretty sure they are advised as the same.
I still think the 350 would always be my first choice, as the flow and chambers are better. Even with the swirl ramp i don't think they will overcome the benifits of the heart shape combustion chambers.
I would like to know the exact reason why the chambers are different between the 305 and 350.
Would a smaller heart shaped chamber be better option for a 305 instead of the swirl ramp? I would think so but maybe not
@@cuttersperformance
Well, if the Stan Weiss flow numbers are correct then the 059's average flow is slightly better than the heads he is calling L31, whichever castings those are?
I kinda want to know which ones I'm gonna choose to start my game plan. Plus the other set will be used on my sbc 307 budget stroker build which will be before the big bore 355 build.
My buddy has never had anything with power (every thing stock). Now he has two c20 chevys a 72 and a 77. Both have upper 100k miles. Not worn out but tired. What do you think of those vortech 305 heads on a 350? I doubt he will ever rev over 4500. I'm thinking the compression increase should give him the thrill of power without giving him more than he can handle.
Even the 305 vortecs will outflow most stock cast iron gm heads, they dont have the good chambers but as long as the compression isnt too high and you can keep the detonation down they should work good
Some 6" I beam rods and some hypereutectic pistons with a little less cc relief than you need so you can then take a dremel and smooth out every sharp edge on top of the piston and in the chamber then to cc to your target cc. This is a hotspot reduction , whereas the heat builds in sharp and thin or pointy areas as seen on a heat signature analyzer.
So how would the Vortec L30 heads work on a TBI 350 vs the Stock TBI heads when going with a jegs dual plane intake and a 650 cfm AVS2 carburetor? A dyno test between these two heads would be interesting on a TBI 350 shortblock. The test would be nice even with the small factory TBI cam just to see the difference. Also,
When will you test the new summit hydraulic roller cams with LS firing order for SBC? Thanks
How does it compare to the 601 and 416 305 heads? Thanks for all the good information
Stock 305 vortec will usually outflow professionally ported 416 heads
@@cuttersperformance ok thanks i have a bunch of 283 cores that could use a good flowing head. On the 350 vortec heads is there a domed pistion available that works with that style of chamber. Or will it wreck the flow and flame travel? I would love two put a set of vortecs on a dz 302 to see the outcome.
The general consensus is that flat top is the best with these combustion chambers. But a small dome would work just fine
darn i need to know how to that valve spring kit you talked about and showed fixs a big issue ? thanks for video
Call me easily impressed but those numbers were better than I expected! I've got a 305 vortec motor and I'd like to build it, this is good inspiration.
Question on your spring kit, how much lift does it alot for w/o machining the guides? Do you think a cam with .575 valve lift (comp's XFI 218/224) would be too much for the flow on some ported 520 heads? Following with that, in your opinion would the heads benefit from 2.02/1.60 valves (if there's even room)? This video really makes me want to build a set of iron heads & make an 11-or-so:1 engine w/a small dome piston & that camshaft... I'd love to hear your thoughts & thanks a ton for the great content!
You should read some of David Vizards books good info on big valves.
Hey cutter great video. I have a question for the vortec man. If I were to switch my l31 to carburetor, i understand that I would need a shift box but would the 4l60e shift manually on the column. Thanks Pat. Keep it up
Yeah you will need a computer for it to operate.
I've seen kits that put them into a manual mode but they won't last long like that. Your best bet would be to go with a stand alone trans controller
I went holley sniper on my c1500 and went with the Fi tech trans controller (not the greatest but it works)
Thanks Pat, your the man. I'm loving all the great content. Stay safe
Have u flowed the 305 416 heads, I want to put them on a 350?
What do you think of a 305 block with a Scat 3.75" crankshaft?
A .030 overbore with a good set of pistons with a compression ratio between 10.5 to 11 to 1. With a decent roller cam with at least .525 lift to get you around the flow curve and out on the straight on both the intake and exhaust. With a set of your ported 520 heads, I'm thinking it would be pretty stout, you should try it.
Well even with a 6" rod your getting only a 1.6:1 rod ratio and that is terrible, No i would go 1.825" radius 3.65" stroke with a 6.2" rod and 1" piston that is if your deck comes up to 9.025" and that i doubt. People i would really just keep the stock crank and buy a DART TAll DECK 9.325" deck height block. use long rods build a custom piston and forget heads for now. You can get it in 4.165' finished bore after you machine it, then you got a great 377 383 style engine that is gonna force heads to comply at low rpm And the basis for a big head forged crank if later on you decide. But think of the street engine that would become Just having ONLY the block! (People , come to your senses. lol .joke.) but seriously it is a good idea ? no?
KB makes a 305 piston specifically for that combination.
Thats a 334 , im building one now, i like the concept of a "square" motor and there was a university study on bore and stroke relationship that i read that says that combo should be really efficient, its going in a s10 , should rip, we'll see.
@@zAvAvAz i've read what you wrote there 4x and my conclusion is you are off your meds !
@@luckyPiston I have had several 305's (150,000 miles+)in my v8 s-10 blazer over the last 20 years. Just down and dirty (very down dirty)re-ring jobs with nothing bigger than an Edelbrock 2102 performer cam, stone stock heads. They don't have the low end punch of a 350, but after a while I forget about the numbers and just E.T. foot brake it with great success. KB makes a 305 stroker piston, and I want to try it with some vortec 305 heads, could be fun, and nobody going to buy these 305 blocks from me. let us know how the 334 turns out.
What program do you use for the flow chart? Good info, I had a set of them years ago but never flow tested them after finding out that they were different from the 350 vortechs!
Do these heads require the same machining or beehive spring upgrade that the 350 heads require to use a muscle camshaft?
Yeah they do
I say bigger exhaust valve in 305 head 🤠 cleaner combustion chamber more explosive mo-power ! 😜😉🤠
Wonder how the 305s would do with the intake cut out to 1.92
Well. they would do well. however i tend to favor more unshrouding of a valve over that. And the angle cuts and weight and smooth reliable actuation and seating. conical springs. The correct pressures and rev kit for more stable smoother operation. i would fill the chamber and reshape while unshrouding. Get 48cc -54cc. And a thin piston with valve reliefs and cupped chamber shape in piston. A 6.285" rod for 1.8:1 rod ratio and reduced wear and a specialized 1" daily driver piston with the ringlands squished above the pin bore .7,.7, 2mm gas port style RINGS. Off the shelf pistons do not duplicate this daily driver ability. or you could use a 6" rod for 1.7:1 ratio. and a 1.260" piston in an undecked 9.025" block with good trueness Of course 305's deck comes in different so sizes would have to be adjusted namely the piston height. A .040" head gasket. If i can get all this then i shall use the 1.92:1 valve.
Thanks!!
It would be interesting to see dyno results on a 305. 305 vortec heads vs 350 vortec heads. I wonder if the ramp is needed to preserve swirl due to the small bore or to increase velocity for low end torque and fuel economy. I can only imagine that if the 350 heads worked better on a 305 gm would have used them instead of designing a whole new head.
Yeah that would be fun, maybe a Mexican casted 350 head vs a 305 head. Similar flow but different designs
Don't forget the 305 was designed to be an economizer version of the 350 so swirl port could certainly be part of the equation.
As for increased velocity i dont think thats what a swirl port is about , think more about mixture quality for combustion....
it would be nice those what those 305 heads would do on a 350
I'm building a motor for my truck and picked up a pair of 059 heads from my schools shop and going on a 350 stock bore flat top pistons but in struggling with choosing a nice budget cam and lifter combo any suggestions?
Great stuff.
So the Stan Weiss flow numbers were a bit enthusiastic for the 305 Vortec heads then? But those were 059 heads so those could be the better ones?
The exhaust numbers are very close to the Stan Weiss numbers, his maxed out at 163 CFM @ .500" lift. The low lift numbers were better than the 062 heads right next to the 059 listing. They maxed out at 221 CFM @ .500" lift.
Got it pulled up on my confuser, it says Chevy Vortec L31 iron, its not calling out the casting number like it is for the 305 heads.
Now you got me wondering if the 059 heads flow better than your 520s? If its not to much to ask, if you find a set of 059s it would be great to know if they do in fact flow gooder like the Stan Weiss website says? Thanks for your hard work making these videos.👍
Can't wait to see what bigger valves and some port work is going to do for those! Thanks.
I'm looking at building a sbc 352, its a sbc 400 block with a 3.25" stroke crank. HRM did an article back in the late 90s called;
"The 350 engine Chevrolet should have built."
I would post a link but yt is getting weird about doing that. If you do a search you should be able to find it easy enough.
Yeah I'm going to try to pick up a set of 059s for a comparison video. I'm also curious as I've heard they may flow abit better
Stan's info is mined from all over and some in my opinion is sketchy here and there especially when it comes to the swirlports , the net is swimming with misinfo on those heads so beware.
A 352 eh , well i did 372 once, thats a 400 with 350 crank, so same idea, destroking a big bore.
I ran it as a short track motor and loved how smooth it was an reved so sweet on the top end, i went to full on 400 later and that motor was just to explosive , i could just never get hooked up where the 372 laid the power down in a controlled way and made it easier to be fast.
@@luckyPiston
Well, it's going to be closer to being a 358 because the block will be .060" over. Because the block needs to be bored to .060" over is the reason why I'm going this route. The shorter stroke will reduce piston speed tremendously, that with the reduced cubic inch displacement should help keep it from running to hot?
Plus if I can duplicate the torque and HP numbers from that HRM article, that would be just right for what its going in without having to worry about breaking the components behind it. It should get decent fuel economy as well with 400 ft lbs of torque starting at 2,500 RPM with O/D!
@@luckyPiston
I wouldn't really call the 305 Vortec heads a swirl port head, they're 2 different series of cylinder heads. The swirl ports were from IIRC around '87 to '95 where the Vortec series are from '96 to 2002 and those include the 305 Vortec heads. The only similarity is the very small ramp the 305 Vortec heads have but the difference being half the port isn't closed off like the swirl port heads that came before the Vortec series.
Besides, the Stan Weiss max numbers were only 4 CFM different than the above non-ported numbers. That small of a difference could be the difference between the 2 flow benches?
Would LOVE to see what the ported flow would be with the ramp left in and also with larger valves! A set of 1.94"/1.60" would be very cool to see how much flow potential there is there with and without the little ramp. Using these heads on 350 or more cid with 1.94" valves would have plenty of room for unshrouding to pickup a bunch of easy CFM. I would almost bet they might even flow better than the 350 ported heads with the same size valves?
Maybe Pat in the shop will do a video covering this? Hint, hint. LOL
Hey man do you think a 1.94 valve would actually help or hurt flow on those heads? And would they beat a 305 HO head?
I honestly believe these 305s would flow the same or very similar to the 350 vortecs with a 1.94 valve. I haven't had a chance to do try this yet so its just a guess.
The biggest downside to the 305 vortecs is they don't have the good heart shaped chamber
The 305 vortecs are the best flowing production 305 head. The stock 305 vortec head will usually outflow a professionally ported 305 HO head.
are the 305 vortec heads prone to easy cracking like the 350s ? , thanks
Swirl port and swirl bore are two different things, i don't think we have air flowing from the port to the bore like a corkscrew, i think the design is primarily promating flow into the center of the bore which leads to more efficient burn as the mixture is filling the cylinder in a more uniform way.
The mixture hitting the backside of the ski ramp is being deflicted down and is helping to turn air on the short side past the valve, there is a convergence that dumps mixture more down into the bore center instead of a non swirl port being more towards the cylinder wall in front of the exhaust valve.
I think people who designed the late model cylinder heads for GM where waaay smarter than anyone ever gave them credit for.
Its actually pretty crazy on how much swirl the ramp causes. Ive done some testing on the flow bench with a velocity probe trying to figure out exactly how the air in moving in a tbi head. The best way i was really tell what's going on is to use a piece of thin yarn. Holding one end you let vacuum pull the yarn into the intake port....the string literally wraps itself around the stem of the valve! Its pretty crazy how much swirl there is... aka "swirl port" haha
@@cuttersperformance I like it. speaking about probes, i bought some 1/8" brass tubing in 12" lengths at a hobby shop and found some string that would fit inside , i worked it down to the other end and i can set the stick out like a wick , i fray it a bit, works like a hot damn for probing around .
@@luckyPiston thats smart, i might have to try that!
Which is better, the heart shape 350 chamber or 305 chamber? Or does a guy go with a 1.92 and 1.6 valve on a 305 head? Does the swirl ramp make a big diff?
The heart shape chamber is much better. Thats the biggest downside to the 305 heads not having it
@@cuttersperformance in the near future im building a 400 small block for my square. Really trying to figure out if i want to mess with stockers or just get some eq heads... you have a good channel, keep up the awesome work.
My question is can you put the 350 heads on the 305? I've heard of 305 heads on a 350 for higher compression but what about the reverse?
Yeah you can, you should have no issues clearing the 1.94 intake valve to the 305 cylinder bore
@@cuttersperformance thank you for a quick response. I was thinking I could just wasn't entirely sure.
Ever dyno 4.3l vortec heads,96-up
Being that you’re a Vortec head connoisseur, what is a fair price to pay for a set? Unless they have been checked, it’s a risk, so the cost has to be low.
If you go to a u pick wreckers, usually $50 to $100 a head
PISS-CUTTER.. I'd like to know exactly what areas of an 062 vortec head to port to increase flow at mid and upper rpm band? As I mentioned in comments a couple months ago, I'm using an L31 longblock to replace a locked up 86 L98. I know the tpi i already a major restrictor.. Tho i have opened up what i can. Now I'm planning on using the zz4 cam with comp cam 1.5 roller rockers. But also have a factory 97 LT1 f car camshaft.. But now have my eye on Summit Racing cam SUM-8801.
Thanks
Its 90% of the bowl work with vortec heads, open the bowl to 88 to 90% of the valve diameter and blend the seat.
So you'll have to obviously use an aftermarket tpi lower intake with the vortecs, which is good but you can't really change the characteristics of the tpi intake, which is low-end power.
I use to do alot with tpi stuff, they are a great street combo for smokin the tires and not a high reving high hp setup. After market runners, ported plenums and the vortecs will help but 5200rpm is usually still the drop off for power, and thats also why you dont want to over cam them
i like the XE256 and XR264HR cams or a small voodoo cam. A roller cam i like the best even though the flat hyd. makes better power until the bigger roller cams take over and then the mech roller. For a great torquey 305 its not going to have top end and rpm shall be way under 6000 rpm for sure. Hypereutectic pistons. It would be great to use 6" I beams just for the fun of it. i am getting 6.160" rods made although i have to buy 100 of them. but that is through hurricane and don't think i want those anymore. I want compstar offset ground crank with small honda journals on the rods and crank. A 1.765" radius /3.53" stroke on an undecked 9.025" block with 6" rods and 1.260" hypereutectic pistons. turns a 355 into a 360 and a 305 into something else. Just better longevity and overall . puts it almost right on 1.7 rod ratio. lower friction. better for wear. Even though the best power comes with a stock stroke and 6.285" rod and a 1" piston with a rod ratio of 1.8:01. And a non turbo or really low boost because of compression and piston shortness with the ringlands squished above the pin bore for daily driving. A custom piston for sure. With even less wear and the best power in a sbc rod ratio.
Can you put the 305 vortec heads on a 350 TBI engine?
Yeah they will bolt to the block but a vortec intake will need to be used
To be clear, you didn't touch the SSR or back cut the valves?
Just the factory back cuts on the valves
I am looking for a set of vortec heads for 305 is there a certain casting numbers I’m looking for or will any of them work
Technically any vortec head will work
But casting #s for 305 vortecs end in 520 or 059
Some claim the 520 flow slightly more but I have no proof of that
Hey Pat if you were aiming to get 1horsepower per cube with a L03 305, would you go with 305 or 350 vortec heads? Other than the cam the short block won’t be touched. I wasn’t sure if the loss in compression and possible valve shrouding would make the 350’s unusable... thanks
Thats a tough one actually
The 350 vortec have the better chamber and better flow than the 305 vortecs.
But like you said the 1.94 valve is abit shrouded on a 305 bore.
I have not dyno tested this but I think a milled down 350 vortec on a 305 with a thinner head gasket to keep up compression would be the best
But if you dont want to mill the heads then I think you may be able to hit your goals with the 305 heads. The certainty flow enough but it is abit hard to make easy power with the small bore
@@cuttersperformance it’d be interesting to dyno test the two Vortec heads on a 305. I’m a bit torn... I’ll keep my eye out for 520’s. Modding the 305 is just a stop gap (no pun intended lol) until I build a proper 350
I do have a old good running 305, ive been trying with the idea of doing a budget 305 build with 305 vortec heads.
What cam were you thinking of running?
@@cuttersperformance that would be awesome! There are still a bunch of the 305’s out there!
I have an L03 in my Camaro, which I believe is a roller cam... I’d actually consider a custom grind. Something around a .450-.475 lift with a lot duration, similar to an oval track “lift rule” cam, maximizing the Vortec’s low to mid lift flow & velocity, and a narrow LSA to help develop low end torque. The lower lift would also be relatively easy on the valvetrain.
"until I build a proper 350" After i built my first 383 vortec i swore i would never waste my time punching any real amount of money into a 350 again, if you ever get a chance to ride or drive a 383 you will get what i mean, something to think about.
Good stuff. Yes a 1.94 and 1.6 valve combo would be good to see on the 305 vortec. Rather than remove the ramp, is there a way to increase the swirl?
Anyone after power and performance would NOT want to increase swirl, that is a tactic for low rpm, part throttle torque and efficiency, swirl limits a head at higher rpm
@@archivegarage7638 That's actually what I was pondering. Maximising torque on a low cube street motor, like a 283 or 307.
depends on RPM usage.
@@archivegarage7638 Curious, how does increased swirl limit a head at high rpm ?
@@luckyPiston Continuing my comment above, the shapes GM used to increase swirl hurt ultimate flow. For instance, the large diameter intake valve boss, the seat choke point, both contribute to swirl. If you want swirl, use them box stock. If you want power, copy an LS3 head which is purposely designed for max cylinder filling. GM stopped using swirl on 6.0 truck motors which says to me GM learned they don't need mega swirl, or were willing to accept less efficiency at part throttle/low rpm
how fo you know if I have a mexican vortec
Its will say made in Mexico but the valve srpings
Great info thanks!
How do 416s look to you?
For my 283 they are free. Or should I find the 520s? Thanks!
Let just say ported 416s will have hard time outflowing stock 305 vortecs lol
@@cuttersperformance 520s it is, thanks again!
so basically a "double bump" head that's not 58 years old for next to nothing?
Oops I meant 1.94
Do you know anything about the 113 aluminum sbc heads going on a .060 400 sbc an what cam to use??
The 113 head has a 58cc chamber. Will make some compression ratio even with a dished piston 400. The intake ports flowed sliightly better than a 882 head. D- shaped exhaust ports are hard to seal with a small tube header.
113 heads will choke the 400 before 6000rpm, and the compression ratio is pushing pump gas. Summit sells an old crane grind 306 advertised duration, 246 @50, and .500 lift on a 106 lsa that would work well given the combination.
You went 060 over on a 400 block? Ain't ya worried about cracks? I know they're siamese bores, but still...Ya might wanna think about a partial fill with Hard Block.
So...whether you have a 305 or 350, is there ever a reason to choose 305 Vortec heads over 350 Vortecs?
I say always go 350 heads if you have option, the combustion chamber is the deciding factor for me even over the flow numbers
@@cuttersperformance New subscriber here. If you were building a truck tow engine and we're looking for low end torque and economy is the 350 head still the better choice? I'm also debating between an LS swap or simply building my 350 do you have any thoughts on which way I should go? Your channel is awesome and I always hit the like button as it helps with Facebook pushing and sharing the video more! Make sure to mention this in a video as I see a lot of views but few old timers who are watching understand how this works and are not hitting the like button 🙂
unshroud the valves at all costs and use the 350 heads.
Do you build vortec heads and sell I want to use a 292 comp cam I can go smaller if I need to
Sorry nothing for sale right now. But with a bit of elbow grease and my videos you can build a nice set of vortecs for fairly cheap
Cheers!
Why not use your 305 heads on a 283, 305 or 307? Prove good usable power is available from these under dog and usually dirt cheap engines.
👍
Sorry the 461x heads are the best out there and not the x on the bottom,
350 tbi engines had those heads
I love this channel, but PISS-CUTTER is a really awful name!
Hahaha its from a sang that a old school mechanic I know uses. I was modifying a cobalt ss when he asked me how much power it made....when I told him, he was surprised and his response was "dang piss cutters!" And me with my wacky sense of humor I came up with Piss-Cutter Performance
@@cuttersperformance Lol. My dad had this odd Midwestern saying that I've only heard from 2 other guys: "I'll be go to Hell". Not "going", just "go".
@@cuttersperformance change it to pizza cutter! yeah thats what he said it just came out like . . . . lol just kidding, but pizza cutter would be aweshome also and the transition would be so close. . . .not any would tell the difference . . ... . . . . .. conan " and laugh" no but really um . . YUM!
ehhhhhhhhhhhhh stock cast iron vortec heads, theyre real weak in the knees. I only use 3 vortec heads, cast iron are Chevrolet Performance 185cc Bowtie, and aluminum AFR 190 street, and Chevrolet 210cc Fast burn. The bare casting on the 185cc Bowtie are part #19331471 $574.25 at Summit Racing and they destroy these weak in the knees truck heads so bad its not funny. Getting a set of real performance heads for just over a grand is a much better way to go. A ported set of truck heads WILL NOT out perform the Bowtie heads andI dont care if Don Garlits himself ported them.
There's no question that lot of aftermarket heads are better but vortecs work pretty good 👌
Just a option for the budget builder or someone in class restriction racing
Makes you wonder why GM even made the 305.. Literally costed the same to produce 305 and 350 but the 350 was better in every area!! Kinda seemed like a waste of time and money producing that boat anchor 305!
It was an attempt at fuel economy and emissions compliance, just like the 262 and 267...
I think these Vortec heads on a roller 305 roller tbi engine, 470 lift cam 600 cfm carb would be a great cruiser engine say in a 50’s pickup.
I bought a 84 chevy 4wd short bed step side granny gear 4 speed with the 305 quadrajet 4 barrel carb. The truck was high geared and it got 19 miles per gallon riding around town and country roads with the AC on. It was great runner too. Hauling ass when I wanted to. 4 barrel would come in at the drop of a hat. So I like the 305 performance and gas mileage. It was a great motor for cars as well
@@drdjh2003 no in any F body . .. yeah.
1st
Blah blah blah.,.. blah blah blah. You yap way too much. Get concise. You waste everyone's time.
Wow dang, this is a older video I’ve tried to shorten my newer stuff abit and talk less. Sorry you didnt enjoy it
@@cuttersperformance Very good that you realize, most of your other vids are not close to as bad. Don't ramble. You came across as a blatherskite.