I put my 64 F100 cab on a 87 F150 Frame. When trying to put the power brake booster on the firewall it hits the cab and won't go back where it needs to go. Years ago Ford Trucks had a spacer that moved the booster out toward the front of the truck. I can't find one and I'm not sure what years they came on. Anybody have one or know what year they came on?
My CPP kit for a '60 Chevy came with a spacer, they might have something for you. Certainly not to difficult to fab something up yourself.