Never ran an 80 but the box 75 on the red truck had a few street miles and was fun and cruised nice. But I tend to run in a higher rpm window than an auto anyway even cruising. I think they just shift a little smoother. I want to run at least a 76 like is on the red truck now on my daily but want a little bit of fuel first, bit I'm not towing and city driving very much at all.