Take a look at this calculator and old video from Spicer it might help.
http://spicerparts.com/calculators/d...gle-calculator We were able to run a 1 piece drive line but kept the same crossmember you have just incase the GVOD was a turd.
Have the same concern about our front driveline it's close and may need to be shortened before taking it off road. Without an add a leaf and the big block my front end is probably softer and it has not given us any trouble so far (rides like a caddy
).