Thanks, that is very close to what my curve looks like. The throttle position is a square wave and RPM is almost square but the driveshaft RPM is a triangle. I understand what you're saying about not knowing how it is going to work until you test it since it all changes depending on the power and the load. At this point I'm just trying to figure out which gear ratio to use. I think I'm going to go with a 3.89 rear gear and assume 10% slip at WOT in the lights.