HP difference between flat tappet and roller lifters

[tarmon8r]

Roller lifters allow a more aggressive profiles, faster ramp speeds so the valve gets to maximum lift sooner, within the same specs as a flat tappet cam. Rhodes lifter "bleed off" some of your cam at low rpms, for example: if you had a real aggressive cam, with lots of overlap and poor bottom end performance, rhoades lifters will make the motor think its a smaller cam at lower rpms and give back some torque in the process, by not pumping up until a certain rpm and "digesting" that overlap, thus reducing bleed off of having the exhaust and intake valves open at the same time as long and there by giving you more cylinder pressure for better throttle response and bottom end torque . and then give you back your more aggresive profiles on the top end when they do pump up. they are usually a little noisy. But your only talking about a minimal amount of impact rhoades lifters can have on a cam.