:confused: I was wondering why you must swap the MC/booster when doing this swap. Visually I can see no difference between the two. Is it a vacuum problem? I can't seem to find anything on this by searching through the site. I know you need a prop. valve and understand why its needed. Just wanted to know the above......

Thanks

FYI: 1968 Chevelle Malibu

Master cylinders are different between disc and drum brakes and will cause major brake problems if not changed. As for the power booster I have done a disc conversion without changing vacuum booster, it required that I make a booster to MC pushrod on my 68, which you would not need to do if one were to replace both as a unit.