[Mike C]

U-joints should be the same. You also need a disc brake master cylinder. The disc brake rubber lines are different, but should bolt to the drum line.

On a 2 wheel drive truck, you need a T-fitting in the front brake lines to reduce down to the hard line from the proportioning valve which you probably will need to source. I would consider buying 71-72 factory from disc lines and replacing the drum lines in full.

The drag link on disc trucks is adjustable but the drum brake one should work. I would consider replacing it just due to age. And it’s not adjustable… Pitman arms should be the same.

I am not sure that the track width is significantly wider, especially 3”, but could be I guess.