[mr48chev]

There shouldn't be a problem there if you bought a matched set of booster and master cylinder. Where a guy would run into trouble there is picking up a booster because it was the right size and then getting a master cylinder because it bolted up to the booster but may not have been intended to bolt to that booster.

If you have ever looked at a number of master cylinders the hole or recess in the end of th piston where the rod goes can vary in depth for very similar looking master cylinders intended for different applications such as one intended for a manual brake setup being put on a booster that needs a piston with a shorter depth of the hole/recess.

I first had it happen to me back in the early 70's while doing a brake job and replacing the master cylinder. Solid pedal but it went down way too far before engaging the brakes. Pulled it back off took it back to the parts house and with some checking of other same number master cylinders we found out that the one I had had the wrong depth of hole for push rod even though everything else looked the same. I ran into the same thing a few years later on a friend's hot rod where he had mixed and matched parts. Everything bolted up but didn't match up. I think in that case he had put a manual brake master cylinder on a power booster on his rig.

About the only thing I can say on that is that the push rod sticking out of the booster should be long enough to go to the bottom of the hole in the piston of the master cylinder when you do some measuring. It's either yup it's real close or nope there is a serious difference.