1.5/ 1.6/ 1.7 ratio rockers

Easy, because you get a larger lift curve, and more flow without having to increase the duration in order to do so. There is a limit, even with our gifted .904" lifter dia. Mopars,
to how much lift you can achieve for a given duration flat tappet cam. More lift and a bigger curve = more torque and HP in the same operating RPM range.