I can give you some advice on the 55-57 trucks. The easiest way to make a 4x4 is to buy a NAPCO front axle and the rear anvil lift blocks. Then have some custom springs arched to your liking, bolt em up to the stock 2 wheel drive Chevy frame. drop in your engine, tranny, t-case, get some custom drive shafts and your done. You will have a strong setup and it will look factory.
Or
If you don't mind the tires hanging out of the fenders, which after looking at that truck you want it is clear you don't care, you can use a 70's Blazer frame and running gear. Weld up some custom body mounts and away you go. Good thing about this set up is that you have a lot of suspension options and disk brakes. You could have the axles shortened to fit under the fender too.
Good luck.
