I would imagine the hole is the same size for both.
Your pedal carrier does not have the captive nuts for the MC bolts to go into so you would have to use bolts with nuts on the back or swap out the pedal carrier. You may want to do that anyway since a power brake pedal carrier and the power brake longer pedal are worth a lot more than the non-power brake set-up to people going the other way with theirs. You would of course have to block off the vacuum port.
Suggestion: pull the entire pedal set-up and MC and booster and sell it as a unit, then buy the cheaper manual brake set-up pedals and a new MC.
I don't know a lot about anything, but I know a little about everything.
Built a 1967 Shelby GT-350 Convertible Replica, a 67 Vert resto-mod and also built a 427 FE 67 Shelby GT-500R (R Stands for Replica). 427 Side Oiler, toploader 4spd, 4 wheel discs, 9" traction loc and a perfect body. What more could you ask for? Now I car hunt and horse trade and I am currently looking for the next project! Always seeking that elusive "reasonable" Shelby.