Thanks for the input guys. The exaust just cant go bigger. I had bigger on another car, and hated it when it was time for plug changes, and this engine bay is just to small. I also have a RPM Performer manifold / with a worked over 780 double pumper. and it does have a snapier bottom end, but doesn't have the pull power through the gear like the tunnel does, maybe it would with a bigger carb???? The bottom end isn't bad, this is a small car, and tends to have traction problems, on street tires, never tryed slicks. T.