Can you put the 73-76 A-Body Upper Control Arms on a 72 and earlier spindle? Need to do some suspension work and have a nice set of later upper control arms around, but no early ones.

It can be done. You need to have the upper ball joint hole enlarged. IT takes a tappered ream. The ream will cost you 80 bucks plus shipping or a machine shop can open them up for you at about the same price. I have the ream and could do it for you but it would be the same price plus freight. The other option is using the early upper control arms from the 72 down A body as they have the smaller ball joint and it fits the 73-76 mounts and is the same length. Or send me a PM and I can answer any other questions on this that you may have. OR buy tubular uppers from Firm Feel that have the ball joint you need. $399.

if its drum brakes if the others were drum it will work but if they came off a dicsk brake car it wont work

I bet you could find someone to swap you out early for late UCA's. Even locally. The late ones are worth more do to the 73-76 disk brake swaps.