I got a 700r4 in my Z28. I'm also installin a 465 in front of it now. It had a pretty well built 383 stroker in it before and it held up fine. The guy I bought the car from said that he carried it to a tranny shop and had kevlar bands and sum other upgrades did to it. That guy said with the upgrades it could handle bout 500 hp. the big block I'm installing now will be a lil above those numbers. If it goes out I'm gonna look for a 4L80E to go in mine. but I guess its according to how much horse you are putting to it too..hope this helps a lil