The pedal ratio is different for power/manual. In many cases the firewall plate will position the booster on the firewall to align with a second hole in the pedal but not sure if that is the case with the '62 B-body. If no second hole, the pedal may have to be replaced.
The pedal ratio is taken care of by the linkage Z bar setup in a power application, no Z bar in a manual
1963 parts book shows 2 pedals, manual or auto trans.
70/71 manual shows the same for A and B bodies, C and D are their own issues.
