No way I'd pull a tranny and not have it refurbished. I would have it built stronger with heavy duty clutches, especially the overrun band for downhill 2nd gear scenarios. 4l80's are strong, I'm not denying that. I am saying they can be built to handle 1000 hp, just as a 4l60e can. I would also add 60's are not junk. At one time they had many design flaws, but racers still use them with corrections.