I re-thot this, they are running the same speed, but the engine is running slower . DUH! But rear gear heat has never been a problem to me. p.s.- I don`t have an overdrive, but would if I could afford one. I run 30" tires on the street, w/ a 3:73 rear gear, will probly run a shorter tire if I ever get around to taking it to the strip.