disc brake question

I have a 70 with 10" drums and am doing the same thing. If you are staying sbp it's a little simpler as you dont need to switch all the ball joints.

I found a dondor car and got;

Master cylinder with booster,plus the inner fender brace from the master to the inner fender.

All brake lines including the proportioning valve and rubber lines to the calipers.

Spindles with disc,caliper,wheel bearings etc (everything hung off the spindle).

I purchased new lower ball joints for a disc brake set up seperately. It's your call. You could get the used ball joints along with everything else.