These gaskets are all about 0-4500 rpms. That's where they shine and add in torque and fuel efficiency. If you own a heavy, tall geared Chrysler small block and are itching for a mileage boost these are for you. Over 4500 rpms their benefits taper off. Being honest I rarely ever take it over 4500 rpms, especially with 2.26:1 gearing and gas prices where they are.

Owner caption March 2011 · Photo 114 of 142