I have a friend that put a GV behind a 4L80 in his old Ford Unibody truck. With the turbo 6.0 LS engine, it's insanely fast.
The trick on the cable operated GM OD trans is getting the TV cable adjustment AND geometry correct. Art has a pretty good article on his website. Make sure you have the correct amount of travel and that the cable starts moving when the moment the throttle begins to open. (I've installed more than a few of his trannys. They work very well).
