5 lug swap Q's

[bglad420]

OK I have a 70 GMC 1/2 ton with drums on all four. rear leaf springs. I tore the guts out of my rearend a while back for my Blazer. Now the blazers gone, and I need a rearend. A guy has a 78 12 bolt rearend. I know the centersection swaps, but what about the axles?? I know I'll have to change all the brakes over too. But heres my main Q he called me today and said I can have the front parts too, they are disc brakes. Will they bolt up?? Pretty new to forum and searching is a bit confusiong for me.

Thanks!