69 K5 disc brake questions

[nicks00si]

I recently bought a 69 K5 Blazer as a project/driver. I got some extra parts with it. Under the truck right now is the original rear end, but the front end is out of a later model blazer, about an 80 maybe? It has disc brakes with new calipers but I have to change out the gears so they match up and install the driveshaft. The later model front end is a few inches wider than the old one and so the truck looks a little odd with such a wider stance in the front. I searched the forums but didn't find much that answered my questions. What I would like to do is use the original front and rear end housings with the original gears. Both have dana 44s but with the extra length I can't swap those out. I need to know if I can just swap the spindles with the disc brakes onto the old housing and axles? I don't know what interchanges and what doesn't and I am very new to 4X4 so any information you can give me would be great. If it comes down to it I will put the newer model rear end under it to match the front and even up the width a bit.
Thanks in advance, Nick