i have done some research and most people switch from the stock 2-bolt master to a 3-bolt booster, what i bought was a 4-bolt that was in a 62' nova and now i have a dilemma. I already popped out the original studs and now i am on to drilling the holes and making a bracket for the inside of the firewall where the new 4-bolt will go, my problem is the flange diameter for the booster is larger than on the firewall and wont fit. the master cylinder hole on the firewall is 2 1/4" and the one i bought is nearly 3". My question is what is the best plan of action towards cutting a larger hole? if pictures are needed just let me know.