first build got 2 parts trucks

[ontariobluenoser]

Hi guys first time here hope you can give some imput on which parts to use
I first got an 80 k10 no motor (was 350) np205 with sm465 trans
d44 frt 12 bolt rear kept frame diffs and frt end sheet metal
second 84 k10 blown 305 700r4 trans and np203 d44 and 10 bolt rear
I have an old 350 stock car motor to use with the 700r4 and np205
Question is whick diffs to use???
The plan is for a mild mud and trail truck 8"springs and 3" body lift
with 38.5 boggers? if poss.
Any imput will be appreciated.