Thanks for sharing. One thing I'd like to add to maybe help others. Having been a Mopar only professional engine builder we had done a bunch of the 516 heads. On paper they made sense. We would put 11/32 guides in them with 2.19/1.81 valves which flowed great after some moderate porting, up to .500 they out flowed The Edelbrock RPm heads. Now here is the important part. I did read at one time that the 516 castings weren't the best for porting since the core shift was bad. Since we were just doing the basic work and not going crazy removing material figured we would be ok. Anyways while just starting to work the exhaust port on one of the heads doing the same work I've done numerous times i barely removed anything and it broke through to water. All the machining work had already been done. Needless to say That was the last time we used 516 heads lol. The LP 915 (1.60) heads are really great especially since HP(1.74) are now much rarer being only available on the 67 GTX n R/T's(possibly others just haven't seen any). All the heads respond beautifully to a 5 angle/radius exhaust valve job so it's simple enough to increase the factory 1.60 to 1.74 or 1.81 without further sinking a already cut 1.74. Even for factory engine builds the performance from idle to redline can be greatly increased 20-65hp(depending on work) with just some basic porting techniques. It's like adding a little shot of NOS but all the time to our otherwise factory appearing rides. Without affecting reliability or visual modification.
The 516 used the old casting technology. The 915 and newer heads used newer casting technology (at that time) to better control wall thickness, besides having better flowing shaped ports. If I remember correctly, this is also when the head freeze plugs changed too. The 2.14" 5/16" stem valves came out before the 1.81" exhaust valves. What we used to do, before the 1.81" valves is, we would take the 1.88" Max Wedge valves and cut them down to 1.83", with a 0.100" margin. The 2.14" valves came out in the 1970's, but the 1.81" valves didn't come out until the 1980's, I believe. I know the 2.14" valves were first and we paired them with cut down Max Wedge exhaust valves, back in the 1970's. The 915 heads flow within 3 percent of the 1964 Max Wedge heads, but flow 10 percent less than oval port big block Chevy heads.
I ported a pair in the day,days of work,then the intake. Did pull allot better. But a 100hp shot was double. Money or time and how quick you want to get there. I'm riding a stock shredder.
Thanks for the info. 915 with the large exhaust valve is the ticket. Unfortunately with all big block mopar wedge heads , they all suffer from the same thing, the valves are not long enough, limits your valve lift, that's why Chrysler brought back the Hemi design, they knew the wedge wouldn't flow for competition.
They did come out with the Max wedge Designs 1st and are found to be competitve in Stock and and Super Stock for many years' But like the other Makers they tossed out great ideas. Now Mx Wedge designed by Ed brock can make 1000 horsepower with the right engine combinations
Mopar had three variants of their heads. You had the stock heads which came in the normal passenger cars. You had the X heads for the 4bbl hp engine. Then you had the U heads that were for the 6pack hp engines. Both the X and the U were clearly visible as was seen on the hemi head that you showed in your presentation. Just a FYI for consideration.
The 1963 300J 557 cylinder heads had "improved" intake ports and the larger 1.74" exhaust valves (sometimes listed as 1.75"). They were also on the optional 1964 300K engine, but not on the standard 300K engine, which had regular 516 heads. The 1967 440 915 heads were later sold as replacement heads for all standard closed chamber heads and were available for service replacement purchase through the 1970's. They had modernized intake and exhaust ports. They flowed within 3 percent of the 1964 518 426 Max Wedge heads, due the internal port shape improvements. Some sources claim the 915 heads were used on late 1967 383 we engines, mostly 2 barrel versions, when the 516 heads were discontinued. All of the late 1967 383 4 barrel Darts I've seen, have had the 516 heads though, so I question this. Some 1971 engines were assembled with 906 heads. Some late 1970's motorhome and police heads have 5/8" spark plugs, instead of 13/16" spark plugs. These heads may or may not have improved water jacket cooling. The nice thing about them is, being able to get a socket on the spark plugs more easily, especially with headers. The cast iron big block Chevy heads are actually heavier than the cast iron 426 Hemi heads. All 1967 440's, including the 350hp version, got a high rise intake manifold to match the 915 heads. All intake manifolds were switched to high rise versions in 1968, including 2 barrels, to match the 906 heads. Even though the intake ports were the same size and location as the 516 heads, the intake manifolds were raised to match the improved intake ports of the newer heads. The exhaust ports were improved also.
@@boydoesititch Was done before the Internet. That was with no porting on either one. The 1964 port designs weren't very advanced and they used to design ports by port volume, not port flow. The 915 head represented modernizing ports at the time and 1967 Pontiac 670 heads did too. The 1963 300J heads had "improved" intake ports and 1.74" exhaust valves. The oval port Chevy heads flowed 10 percent more than the 915 heads and with mild porting, the Chevy oval ports outflowed Chevy's unported rectangular ports, when the big valves were added. The Max Wedge ports were an older design that 915 ports, even though they are larger. They only beat the 915 by 3 percent.
The open chamber ruins these heads because they are very prone to detonation. They have no squish at all due the very large clearance volume and this is a very bad thing. The closed chamber heads would all be much better in this important area. Unfortunately back in these days cylinder head development was not well understood by many manufacturers because the machines needed to do this kind of research had not been perfected such as flow benches as would be later made by Superflow. Having a head with good mixture motion as provided with a small and tight clearance volume is very important to performance as we will see in the best heads produced by other brands. One will notice on every good design a very small chamber and a totally flat deck on the head. The Mopar heads fail miserably in this regard as well as their poor showing on flow testing. It's one of the reasons that these engines never made the power in factory form that other brands did considering their large displacement. They could have been much better if the factory had reduced the high rotating weight that these engines have and done some serious work getting the heads to flow better. I believe that they felt that the Hemi was the engine that people would go for but it was too expensive for most so not many were every produced. Your video is very good and we appreciate the work that you have put into it.
You pointedly skipped over the 401 "Wedge" as in my odd-ball 1958 Chrysler Imperial 4 door SEDAN (yes, I know it was SUPPOSED to have a 392 Hemi, but MINE didn't and I still have the "build sheet" from under the back seat). De-bore a 426 and de-stroke it .32 inches and you have an early Wedge. The Hemi would out-top speed me, but in an 1/8th, I KILLED THEM. For a dozen years MOPAR's 401 CRUSHED all other street engines. Mine had twin AFB's hanging over the exhaust manifolds, and the 4200+ lb Torque-Flite three speed auto returned above 20 MPH hi-way no problem.
Pretty sure that several of the chamber volumes you mentioned are not as cast numbers but rather NHRA minimum volumes, i.e after being milled a substantial amount.
i dont think the 66-74 or so Heads are much different for power levels Just Need larger exhaust valve for Big Blocks. I have a set of 69-70? idk? 906 forever in storage had the 2.14-1.74 Fererra valves .
@smilsmff i hear the 915s are the way to go for performance. They are closed chamber with similar valves if can get the hp 915 heads. Might be able to take non hp 915 heads and just put bigger valves in the too. The set i showed in the video were non hp 915. I'm assuming someone changed to larger valves. But, yes, many of the open chamber are similar. Just check the cc of them. Many later 70s have more cc's than late 60s early 70s.
Turn off the background music while you are talking and explaining things. We have a hard time hearing you. Nothing more distracting than background music when someone is trying to explain important things.
Thanks for sharing. One thing I'd like to add to maybe help others. Having been a Mopar only professional engine builder we had done a bunch of the 516 heads. On paper they made sense. We would put 11/32 guides in them with 2.19/1.81 valves which flowed great after some moderate porting, up to .500 they out flowed The Edelbrock RPm heads. Now here is the important part. I did read at one time that the 516 castings weren't the best for porting since the core shift was bad. Since we were just doing the basic work and not going crazy removing material figured we would be ok. Anyways while just starting to work the exhaust port on one of the heads doing the same work I've done numerous times i barely removed anything and it broke through to water. All the machining work had already been done. Needless to say That was the last time we used 516 heads lol. The LP 915 (1.60) heads are really great especially since HP(1.74) are now much rarer being only available on the 67 GTX n R/T's(possibly others just haven't seen any). All the heads respond beautifully to a 5 angle/radius exhaust valve job so it's simple enough to increase the factory 1.60 to 1.74 or 1.81 without further sinking a already cut 1.74. Even for factory engine builds the performance from idle to redline can be greatly increased 20-65hp(depending on work) with just some basic porting techniques. It's like adding a little shot of NOS but all the time to our otherwise factory appearing rides. Without affecting reliability or visual modification.
Yes. A machinist out here, kim barr racing, said he had the same issues porting on mopar heads as you are describing.
The 516 used the old casting technology. The 915 and newer heads used newer casting technology (at that time) to better control wall thickness, besides having better flowing shaped ports. If I remember correctly, this is also when the head freeze plugs changed too. The 2.14" 5/16" stem valves came out before the 1.81" exhaust valves. What we used to do, before the 1.81" valves is, we would take the 1.88" Max Wedge valves and cut them down to 1.83", with a 0.100" margin. The 2.14" valves came out in the 1970's, but the 1.81" valves didn't come out until the 1980's, I believe. I know the 2.14" valves were first and we paired them with cut down Max Wedge exhaust valves, back in the 1970's. The 915 heads flow within 3 percent of the 1964 Max Wedge heads, but flow 10 percent less than oval port big block Chevy heads.
I ported a pair in the day,days of work,then the intake. Did pull allot better. But a 100hp shot was double. Money or time and how quick you want to get there. I'm riding a stock shredder.
Thanks for the info. 915 with the large exhaust valve is the ticket. Unfortunately with all big block mopar wedge heads , they all suffer from the same thing, the valves are not long enough, limits your valve lift, that's why Chrysler brought back the Hemi design, they knew the wedge wouldn't flow for competition.
They did come out with the Max wedge Designs 1st and are found to be competitve in Stock and and Super Stock for many years' But like the other Makers they tossed out great ideas. Now Mx Wedge designed by Ed brock can make 1000 horsepower with the right engine combinations
Mopar had three variants of their heads. You had the stock heads which came in the normal passenger cars. You had the X heads for the 4bbl hp engine. Then you had the U heads that were for the 6pack hp engines. Both the X and the U were clearly visible as was seen on the hemi head that you showed in your presentation. Just a FYI for consideration.
Post script, the stock and X heads had the same valve sizing. The U heads had larger valves.
The 1963 300J 557 cylinder heads had "improved" intake ports and the larger 1.74" exhaust valves (sometimes listed as 1.75"). They were also on the optional 1964 300K engine, but not on the standard 300K engine, which had regular 516 heads. The 1967 440 915 heads were later sold as replacement heads for all standard closed chamber heads and were available for service replacement purchase through the 1970's. They had modernized intake and exhaust ports. They flowed within 3 percent of the 1964 518 426 Max Wedge heads, due the internal port shape improvements. Some sources claim the 915 heads were used on late 1967 383 we engines, mostly 2 barrel versions, when the 516 heads were discontinued. All of the late 1967 383 4 barrel Darts I've seen, have had the 516 heads though, so I question this. Some 1971 engines were assembled with 906 heads. Some late 1970's motorhome and police heads have 5/8" spark plugs, instead of 13/16" spark plugs. These heads may or may not have improved water jacket cooling. The nice thing about them is, being able to get a socket on the spark plugs more easily, especially with headers. The cast iron big block Chevy heads are actually heavier than the cast iron 426 Hemi heads. All 1967 440's, including the 350hp version, got a high rise intake manifold to match the 915 heads. All intake manifolds were switched to high rise versions in 1968, including 2 barrels, to match the 906 heads. Even though the intake ports were the same size and location as the 516 heads, the intake manifolds were raised to match the improved intake ports of the newer heads. The exhaust ports were improved also.
Flowed within 3% of the max wedge heads? Any source for that?
@@boydoesititch Was done before the Internet. That was with no porting on either one. The 1964 port designs weren't very advanced and they used to design ports by port volume, not port flow. The 915 head represented modernizing ports at the time and 1967 Pontiac 670 heads did too. The 1963 300J heads had "improved" intake ports and 1.74" exhaust valves. The oval port Chevy heads flowed 10 percent more than the 915 heads and with mild porting, the Chevy oval ports outflowed Chevy's unported rectangular ports, when the big valves were added. The Max Wedge ports were an older design that 915 ports, even though they are larger. They only beat the 915 by 3 percent.
Thank you for the detailed information. 🙂
The open chamber ruins these heads because they are very prone to detonation. They have no squish at all due the very large clearance volume and this is a very bad thing. The closed chamber heads would all be much better in this important area. Unfortunately back in these days cylinder head development was not well understood by many manufacturers because the machines needed to do this kind of research had not been perfected such as flow benches as would be later made by Superflow. Having a head with good mixture motion as provided with a small and tight clearance volume is very important to performance as we will see in the best heads produced by other brands. One will notice on every good design a very small chamber and a totally flat deck on the head. The Mopar heads fail miserably in this regard as well as their poor showing on flow testing. It's one of the reasons that these engines never made the power in factory form that other brands did considering their large displacement. They could have been much better if the factory had reduced the high rotating weight that these engines have and done some serious work getting the heads to flow better. I believe that they felt that the Hemi was the engine that people would go for but it was too expensive for most so not many were every produced. Your video is very good and we appreciate the work that you have put into it.
Thank you.
You pointedly skipped over the 401 "Wedge" as in my odd-ball 1958 Chrysler Imperial 4 door SEDAN (yes, I know it was SUPPOSED to have a 392 Hemi, but MINE didn't and I still have the "build sheet" from under the back seat). De-bore a 426 and de-stroke it .32 inches and you have an early Wedge. The Hemi would out-top speed me, but in an 1/8th, I KILLED THEM. For a dozen years MOPAR's 401 CRUSHED all other street engines. Mine had twin AFB's hanging over the exhaust manifolds, and the 4200+ lb Torque-Flite three speed auto returned above 20 MPH hi-way no problem.
Pretty sure that several of the chamber volumes you mentioned are not as cast numbers but rather NHRA minimum volumes, i.e after being milled a substantial amount.
i dont think the 66-74 or so Heads are much different for power levels Just Need larger exhaust valve for Big Blocks. I have a set of 69-70? idk? 906 forever in storage had the 2.14-1.74 Fererra valves .
@smilsmff i hear the 915s are the way to go for performance. They are closed chamber with similar valves if can get the hp 915 heads. Might be able to take non hp 915 heads and just put bigger valves in the too. The set i showed in the video were non hp 915. I'm assuming someone changed to larger valves.
But, yes, many of the open chamber are similar. Just check the cc of them. Many later 70s have more cc's than late 60s early 70s.
Turn off the background music while you are talking and explaining things. We have a hard time hearing you. Nothing more distracting than background music when someone is trying to explain important things.
I 2nd this. Good info though