Quote Originally Posted by 64GunPilot View Post
An episode of engine masters proved that 1.5 stamped steel and 1.5 roller rockers had identical numbers, but 1.6 RR improved their test engine by 15hp / 6ftlbs. But their test engine was heavily modded and rev’d up to 7k. I think 1.6 might squeak another 5hp and maybe 5ftlbs. I don’t want to do any restrictors so we’ll see.
Something to consider:
*Where* in the power curve do the 1.6 rockers make a difference?
Where is the peak torque? Remember that HP is a calculated number based on torque and RPM.
So a little more torque at 2000 RPM doesn't really make a big difference in HP; a little more torque at 6500 RPM will bump HP up more.
Your TPI motor runs out of air at 4500-5000 RPM so torque falls off fast and you are forced to shift. However, the 1.6 rocker will let the motor
breathe a little freer at low RPM (so for us math nerds, more area under the curve), likely giving you a little more pull coming out of a corner or
slightly better acceleration for standing and rolling starts.

And if you have to go the restrictor route, talk to the guys who use the exhaust pipe restrictors. My experience dealing with the #39 car
is with the throttle body restrictors we had oil collecting in the throttle body and intake due to the way the air flowed through the restrictor
plate. I don't know if there was some sort of venturi effect or what but we always had oil around the restrictor plate. Sean (#15 Stormtrooper Car)
and David (#39/#88 recently) went to exhaust restrictors and I think the engine behaved more gracefully at mid-high RPM. But as you say,
no restrictor is preferred.