ZF six-speed conversion

Whats up chevyland! I'm interested in converting to a ZF tranny behind a fuelinjected 383 tuned for towing and highway travel. The underbody clearance is not an issue (will be using a 40's-50's C.O.E. body with fabricated sleeper) This would be on a 83 Crewcab chassis. Mounting should (except for the shifter) not be an issue due to complete custom body. Has anyone put a ZF to a smallblock? How did it go? What would be a good diff. gear ect. THANKS!