1985 D150 SWB 904 to 727 swap, need driveshaft length!!

Going from 318 with 904 and 9-1/4 rear to 727. Trans is out of a 78 LRE, with matching convertor.
Anybody know for sure the length I need?
Any oddball stuff to look for or avoid?
Suitable donors besides SWB 72-92 pickups? (Rare in Texas junkyards)
2WD Ramcharger is same? (Pretty sure, but never hurts to ask)
Vans?
Later models?