T.B. from 3.0 M.Sport is like 80mm. 2different TBs are used and 2 different ICS. Vacuum damper for EGR is in the vacuum hose and not in casting as in '89. I was going to do this because my '89 water heated air controll went bad. I modified it to get by.
Some 92 SRs came with 4.88 and airlocker. The problem is they have high pinion front diff.
IMHO your looking for slight (if any) improvement, and gonna get headaches and waiste $.

dave h.
'89 Raider V6 5spd;Aisin Hubs;; Gen2 LS: frt. brakes, rear coils;U.C.arms;R.trailing arms;idler arm; rear LSD axle w.disc brakes ;2 battery system for Dog's fan; relocated ECU; custom bumpers;J.Baker receiver;Conferr roofrack; t-bar crank.