87 ranger engine swap?

i have a 87 ford ranger stx with a 2.9 v6 and a 5spd trans..has 4wd. does anyone know what motor/trany combo will work thats bigger than 2.9 and will fit up with my current transfer case?

i think a 4.0 will work not sur but if my facts are correct the 4.0 will bolt up to you 2.9 tranny and transfer case but you have to change the computer for the electrical..i have been told not for sure so migh twant to chaeck with someone else...