- Joined
- Jan 13, 2012
- Messages
- 1,989
- Reaction score
- 8
- Location
- Washington
- My Car
- 1971 Mach1, 351 Cleveland, Ram Air (not factory), C6 Automatic, AM/8 Track, Bright Red.
I was hesitant to remove my 2V heads and put on 4V closed chambered heads on my 71 M code (previous owner had removed the 4V heads). I had read a lot about the 2V heads having better low end torque and street manners plus the closed chambered 4V needs higher octane fuel. ..but I went ahead and did it.
All I can tell you is I like the performance with the 4V heads MUCH better, I'm running the same 92 octane ethanol free fuel and same carb, there is no pinging, no low end torque issue and I can tell (seat of the pants) there is more power through out the RPM range.
The 2V heads had less than 5,000 miles since their rebuild so I don't think that was an issue in the comparison.
Of course I had to also swap out the intake and exhaust manifolds but I went with the same Edlebrock Performer intake but a 4V verses 2V and swapped out the stock 2V exhaust manifolds with 4V stock manifolds. So it's apples to apples with the exception of 4V verses 2V.
My personal experience - 4V closed chambered heads over 2V heads, yeah baby.
My thanks to Don of OMS for finding me a set of great date matching 4V heads for my 71 M code.
Jim
All I can tell you is I like the performance with the 4V heads MUCH better, I'm running the same 92 octane ethanol free fuel and same carb, there is no pinging, no low end torque issue and I can tell (seat of the pants) there is more power through out the RPM range.
The 2V heads had less than 5,000 miles since their rebuild so I don't think that was an issue in the comparison.
Of course I had to also swap out the intake and exhaust manifolds but I went with the same Edlebrock Performer intake but a 4V verses 2V and swapped out the stock 2V exhaust manifolds with 4V stock manifolds. So it's apples to apples with the exception of 4V verses 2V.
My personal experience - 4V closed chambered heads over 2V heads, yeah baby.
My thanks to Don of OMS for finding me a set of great date matching 4V heads for my 71 M code.
Jim