I've got a big project coming my way and I need some help because I absolutely have to get it done.

Here is the project.

Current Stats:
1985 Chevy C-30 2 wheel drive mason dump Blown Chevy 350 crate engine Standard trans L-1-2-3. 4:11 gear ratio no a/c broken heat needs some body work.

Stats on what I want to do to it:
1985 Chevy C-30 4 wheel drive mason dump 6.2 diesel engine standard trans 3:73 gear ratio has A/C.

I am getting the truck from my uncles roofing company for free and my plan is to restore it because it has a lot of sentimental value to me and him. My cousin has a 6.2L diesel currently hooked up to a automatic trans its in a truck and has 46k original miles on it so i can get everything down to the wiring and a/c unit on it. So that part of the swap should be pretty simple because I will have everything I need. Here is where I think it will get a bit trickier. I want to turn this c-30 into a 4 wheel drive truck. I have gotten mixed reviews as to how difficult it really is. Some have said its simple you just unbolt all the front end stuff and it should bolt right in and you can move a cross member to bolt in the transfer case. A few other mechanics I know say it would be easier to get a 4 wheel drive truck and chop the frame and weld it under my current c-30. I dont know what I should do Need some advice there. Other thing I am going to do my buddy has a slightly newer k30 4 wheel drive and he has 3:73s in it and gets decent mileage with it but he has a different standard trans. He has the L-1-2-3-OD. I want to put 3:73s in my truck and I would assume I should change the trans with it. But if i can get away with just changing 3rd gear for a more highway speed gear to keep my trans I will do that. So I am looking for a ton of advice hope I can get some good help from you all.

I know it will be a long costly project but I want to make this truck my general do everything truck. I will be doing a complete restoration to the truck. The diesel engine and all parts to drop it in will be very cheap if not free because a few years back I helped my cuz out and gave him an old truck so that cost will be low. As for the rest of the 4x4 conversion (front end transfer case driveshafts) It really depends on if I can purchase a whole truck to steal off of or if I would have to buy each individual piece. And wherever I have to mouth the transfer case there is a local driveshaft shop down the road I can get custom shafts built for me. Obviously I would love to keep the cost low, Probably wont happen but whatever needs to be done I will do because I know what I wantand I know it is do-able. Thanks for any help.

~Ray