For an 80 LUV, look for a 5 speed in a 2WD pickup, 84-87 with a G200, or you might look at pickups up to 93 or so with the 2.3L 4ZD1. Those are your choices for a 5 Speed with a cable clutch setup like what you'll find in an 80. You could look at 83-89 Impulses for the trans, but they are hydro clutch, so you'd need to swap all the hydro clutch parts from a 76-77 LUV including the bracket under the dash the pedals hang off. All Troopers are 4x4, so unless that is your goal stick to pickups.
For the motor, 84-87 pickups or 84-85 troopers will have a G200 in carb'd form, or you could find a FI G200 in Impulses from 83-87. The Imp motor has a bit higher compression ratio so it will give better performance, although if you want to run a turbo with a lot of boost you might want to stick to the motor found in trucks. The difference will not be that noticable if you keep it carb or just FI, but if you get detonation with the turbo because of too much compression things will break pretty fast.
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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)
MEPR: Man, my 4x4 makes all other LUVs look good
