4cyl and v6/turbo CAN be swapped.
What you need is the front AND rear diffs out of a truck/4runner, since yours is IFS, it uses a different (7.5 vs 8") ring gear. So you cant get 2 seperate 3rd members, it'd be easier to pull both out of the same truck.

89 4Runner
3" BL, M/T locks, 33"bfg mt, bilstein, Kayline, tubebumper, toyotafiberglass panels
TBI: Elocker,3.4 w/ORS,b+b,S2Sstg2cams,arias pistons,P+P intake,TRDs/c,URDpullies+7th,downey headers,MAPECU2,WEGO WB, SupraMAF,walboro255,stg4clutch, EPaOo2 sim