Need Parts help!

Hey guys im a recent high school grad and i have a 91 b2600 i blew up graduation night.. i got a guy with an 86 b2600 and he says the front diff is out and that mine isnt compatable. mine is a manual his is an automatic.. i just need a little guidance any help?? Thanks

my bad 89*

the 2600 and 2600i are 2 different motors produced by 2 different manufactures. one is a Mitsu the other is a Mazda.

same truck and motor and all, there both b2600i but different transmissions is all i didnt know if my front diff was the same. the other truck is much nicer and i was gonna use my 91 for parts..

if they are both the 2600i then everything should be the same. even auto to manual trans.