I can get M body spindles, core calipers & slider brackets, backing plates, with the old lower Ball joints attached. Question is who has done this swap on a 71 a body with 10" brakes?? Do I need the later 73-76 A body upper control arms ? Do I need the later a body spindle lower ball joint? I want to put 15" rims up front so I can just order 11.75" rotors correct? What hoses do I need to order? Guessing I need a adjustable proportioning valve to work with the stock drum unit. Sorry for all the questions just tring to get it straight to see if it's a good way to go.

You need to get the adapters that fit the 11.75" rotors. the M body ones are for 10.87" rotors.

You need the control arms, not sure on the lower ball joints, been a few years.

You can run 73 and up A body disc hoses is you mount the calipers like they are mounted on stock 73 and up disc A bodies, otherwise I use 79 F body hoses and remove the bracket.

Run the combination valve off the M body if it has the same diameter rear drums as your A body. The aftermarket adjustable valves are best used to fine tune stock proportioning, if needed. Some will tell you that they work just fine by themselves, those people know nothing about braking systems.

dr. diff has adapter sleeves that adapt the small upper ball joint to the large ball joint taper. i have used these in a 72 duster drum to disc swap, and they work great !

I forgot about those adapters. I need a set for my Cuda, or maybe I'll just buy new control arms, still pondering it right now. Hotchkis makes some nice ones.

You need the lower ball joints for a 73-76 A body car.

The upper you can use the Dr Diff sleeves or swap to the 73-76 style UCA.

Hoses depend on how you mount the calipers.

Ok, the setup I may get does not have the proportioning valve, but guessing that won't be hard to find, I have 10" rear drums, guessing most of those M body's had 10" also. I don't need to use 11.75 rotors would just be nice. Did you guys use the moog problem solver offset bushing also?

Civilian M bodies used 10" rear drums, cops used 11" rear drums, same fronts.