But, a large change in lift ratio that increases mid-range duration significantly will move the engine’s power peak up the rpm scale. That’s why wild cams with lots of duration and valve overlap that produce tons of high-speed horse power are typically bad for low end torque, idle quality and everyday drivability.
Cam Advance and Retard Advancing or retarding the camshaft moves the engine’s torque band around the RPM scale by moving the valve events further ahead or behind the movement of the piston. Typically, a racer will experiment with advancing or retarding a cam from "straight up" and see what works best for their application. Mopar 383 Pistons and 383 Stroker Pistons. The Chrysler 383 V8 engine was in production from 1959 through 1971. While most people are familiar with the B engine 383 which used a 4.250 bore size and a 3.375 stroke crank, there was also a few RB based 383 engines built in 1959 and 1960.