With Rhoads Lifters you can run more cam and still have great low-end torque, engine vacuum and idle quality. The secret? Variable Valve Timing! Rhoads' exclusive patented design reduces lift and duration on the low-end and restores it on the top. This lets you run more camshaft while retaining great low-end streetability, fuel efficiency and better emissions. And they are anti-pump-up for maximum high-end revs. This makes Rhoads lifters ideal for high performance street, marine, strip or oval track.