If you have a choice, use a short 727, truck or motorhome. It puts the overall length slightly longer than stock so it doesn't make driveline angles as much of an issue. They advertise a Shorty version but I'm not sure if it uses the above mentioned trans or if it uses a 4x4 case. If it uses a 4x4 case it would be really short and probably would not work with a factory rear mount system.

The GV does have the advantage of being able to split gears so you wind up with a close ratio 6 speed auto, something a 5.7 could take advantage of.

Kevin