So I just bought a 2002 Chevy express 2500 conversion van it has a 350 with 247,000 on it. we plan to put a lot of miles on it. My goal would be to put a 383 in it and convert to 4x4 doing all the work myself. Just wanted some opinions as to what mpg might be looking at and what the cost might be.
Hello Mr87, Welcome Aboard, and Grats on the Van too! I'd say go with what you want motorwise, the 5.3 will require a computer, potentially, another $1000?
If you want to convert a Van into 4x4, assuming it's a Leaf Sprung Straight axle set up you're after, the GMT platform may not be quite as straightforward or as bolt on as a G series would be to convert. I'm not sure if major changes were made to the frame from the G series? Not saying it could not be done, but the later model factory 4x versions of the Vans are an all wheel drive, no locking hub independent type system.
So. There are a few 4x Builds on here you can search. You'll need a 4x front end, suspension, steering. Transfer case, maybe a transmission, linkages driveshaft, Wheels tires shocks etc, etc. I am not a car builder, but I'd say Parts, 5k+ Easy. Good Wrenching, and again,
P.S. The Holy Grail of 4x4. 454 G30 EXT Factory ordered conversion