My 67 has factory power brakes with front disks. The plan is to upgrade to 4 wheel disks down the road. In the meantime, my master cylinder appears to be leaking between it and the booster. I need to replace it asap but I would rather replace it with a master cylinder that will work for the upgraded 4 wheel disk setup in the future. Just trying to avoid buying two master cylinders if possible. I can get a new stock replacement for $50 but not sure if it wil work for the future upgrade. Any suggestions are appreciated.