[flipper35]

Ernie, the lifter bore determines the ramp speed on a non-roller cam. Chevy has a .842" bore and Ford has a .875" bore. The larger the bore, the faster the rate of lift you can grind into the cam. Some cam companies will do a generic grind to the lowest common denominator (Chevy) and apply that grind to the whole line. Some now are grinding brand specific ramp speeds to take advantage of the differences. You also get a better idle for the same "duration".