Heim, you have a pretty ambitious plan there. Sounds like the plan is bad or you have the wrong truck to start with (You asked for opinions , right?) A C20 is pretty badass truck to start with and is well suited to do a variety of tasks. But to convert to 4wd will be a major hackarama. If you do as 48 suggests and put the truck onto a whole new 4x4 frame, well,frankly you don't have your family's C-20 anymore do you? The blower and new engine are all cool and all, but in this economy, do you really need that stuff? And spending the money and engineering effort on all of that? Here's my 2 cents. Throttle back! Put the truck into an outstanding mechanical condition first. Top notch brakes are first and foremost. Then get that 292 up and running. Do you know anything about 292's? They have incredible torque, have 7 main bearings, will get "decent" fuel mileage and be reliable as rain. Then bring the cosmetics back to where you are pleased. You say you know you need a new rear axle and all. Not really. A more modern 5 speed transmission has been successfully installed by probably hundreds of guys into these trucks. Old school overdrive transmissions are another option. I suggest a serious rethink of the priorities of your build. Sorry to pee on your parade, but that's the view from here.
( I assumed a 292 in there, but you didn't state that in your post)
