we want to do away with the old Chevy master cylinder. the owner wants a double master cylinder for safety reasons and because we added rear discs, wa have to add a booster. all this and he won't give up his 4:1 ratio swing pedals, or his 351 Cleveland motor, so we are going to double bellcrank under the floor for a 7" double booster. All this means a new Clutch master of some sort. I would rather do a retrofit as opposed to a Wilwood. No reason, just Me.