Hey just help but yea they did make a 10” front drum for a bodies in 73-76. Given ma mopars propensity to repurpose parts I’m sure one of those would work.
Now I start down a new discussion that will light this thread up. The B Body 10” drum spindle is the same spindle as the later A. So a B body lower ball joint and spindle should work.
Upper control arm you would use a 73-76 upper control arm.
The control arm change is mandatory to change to big bolt pattern.
Now that we’ve discussed what has to actually change on the suspension, I would strongly recommend buying the front disc conversion. All the parts I just said that need to be changed will come new. The rear you can swap the axles in the 7 1/4 or find a later 7 1/4 complete.
Your location is So Cal mine is as well. PM me I have a 7 1/4 I’m willing to give to the first taker.