[Zman1969]

I replaced a booster and master on a 69 Firebird frt disc car with repo parts, I had to shorten the pin so I shortened the long one first (this way I'd have 2 chances)it had to be shorter than the short pin IIRC I took off over 1/4" gotta love aftermarket parts - sounds like it needs to be a little longer?
when you bolted the master to the booster did you have to push it back to get the nuts started? then the pin would be too long as was my case. you verify the booster is in the correct hole on the pedal?