[Super73]

TH350, 4.56 gears, and 33" peaked at 4900RPMs, the valves float at 5200RPMS.


By these figures (5k rpm) assuming 5% verter slip, this would only net you 102.3mph to work with. With that alone, it's going to be hard to go faster than a mid 13 with an optimized set up. With 252hp I figure your really only going to get to a low 14 assuming you are 3,800ish race weight.

I would bet that with just the head swap you would pick up both RPM and power. I don't think you'll pick up a lot with just heads, but probably 5-10% in both catagories if I had to take a guess.

The cam is definately going to move your RPM up with the mentioned heads. How much is really going to depend on where you position the cam in the motor, and the rest of your valvetrain.

I'd see what happens with your existing headers before you swap them. This way when/if you swap you can decide what was better for you.

Do you have a factory verter now?