Front disc conversion

Power booster can stay. Distribution block can stay if you add an adjustable proportioning valve the rear line. Or replace it with the later factory combination valve. Master cylinder should be changed, the drum brake MC has the reservoirs evenly split, on a disk MC the reservoir for the front disks is larger than the one for the rear drums. Unless the plan is 4 wheel disks, then it can stay if you remove or defeat the residual pressure valves (if they’re even there).