Can I use a master cylinder off a car with disc/drum on a disc/disc conversion?

This is well documented, and is in all the service manuals. Download one from MyMopar

you can use small sheet metal screws forced into the seats to pull them out with a claw hammer. I used my original 67 master with 4x disk brakes. I didn't even remove them!!! I just took a nail and punctured 'em from the outside LOL

Thanks, that looks pretty simple.