The 4.3 swap is one to search. Lots of past threads and a few now running that drivetrain. LandRaider was an early one and yes, he most certainly did the work himself.

Search the past threads, then post up you specific questions and answers will abound. There is also an article in the Mitsu Tech area from when Bob Shaw did his a few years back now.

Big Truck: 00, 3.5, Endeavor, 5-Spd drive line in hand!
Little Truck: 87, 2.6T I/C, MT, LSDs, Tonneau Top
Her Truck: 03, 3.8, 20th Anniv, 65k
Daughter's: 06 Eclipse, Keeping it Mitsu!
FSMs: MitsubishiLinks.com