IMHO, I don't think the 3650 will hold up as well at the 4R70W. I had a 4R70W in my '98 v6. When I sold it, the car had 107k on it and I had not one problem with the tranny. I had 3.73's in it too from about 25k on. I beat the living piss out of it on a daily basis, at the track, and I even did...