Hello everyone!
I have read these forums for awhile, but first time posting here, so thank you in advance for any advice.
I have a '86 Cutlass with the vin 'Y' 307 engine. When I first got the car, I put a performance Edelbrock intake and heads on it, because it was cool and I was 16 and had no idea how to properly build an engine at the time.
Years later, I realize that the performance intake and headers are doing nothing for the engine since the heads are still the stock 7A small port heads. In fact, many claim that due to the port size mismatch, the intake and headers actually hurt the engine performance due to turbulence. I have read online that the early 80's 5A heads are a direct replacement for the 7A heads and flow significantly better. I have a donor engine, and I plan to keep everything from the 7A heads (springs, rockers, push rods, lifters, valves, etc).
Is it true that the heads are identical except for the port sizes? I plan to take a ton of measurements and compare the heads, but knowing ahead of time that they can or cannot be swapped would save me some time and energy tearing the donor engine down.
Also, this is a low budget build. I really do not have the money to get the current 7A heads ported, built or swapped with anything high performance. I am working on the 307 this winter anyway, because it has a few fluid leaks and needs some gaskets. I am just looking to help the current engine build breathe better, and I would like to keep the current mods because my dad and I built the engine together, so it is special to me.
Thank you in advance for any help and info you have!
I have read these forums for awhile, but first time posting here, so thank you in advance for any advice.
I have a '86 Cutlass with the vin 'Y' 307 engine. When I first got the car, I put a performance Edelbrock intake and heads on it, because it was cool and I was 16 and had no idea how to properly build an engine at the time.
Years later, I realize that the performance intake and headers are doing nothing for the engine since the heads are still the stock 7A small port heads. In fact, many claim that due to the port size mismatch, the intake and headers actually hurt the engine performance due to turbulence. I have read online that the early 80's 5A heads are a direct replacement for the 7A heads and flow significantly better. I have a donor engine, and I plan to keep everything from the 7A heads (springs, rockers, push rods, lifters, valves, etc).
Is it true that the heads are identical except for the port sizes? I plan to take a ton of measurements and compare the heads, but knowing ahead of time that they can or cannot be swapped would save me some time and energy tearing the donor engine down.
Also, this is a low budget build. I really do not have the money to get the current 7A heads ported, built or swapped with anything high performance. I am working on the 307 this winter anyway, because it has a few fluid leaks and needs some gaskets. I am just looking to help the current engine build breathe better, and I would like to keep the current mods because my dad and I built the engine together, so it is special to me.
Thank you in advance for any help and info you have!