I have what I was told is an original power brake booster for a 67'. I am confused as to how the booster is attached to the firewall. Is there a bracket that interfaces the two. Looking at the Classic Ind catalog the booster has three mounting bolts and the unit I have is the same. The foot pedal bracket mounts through the firewall with two bolts that mount the non power master. Anyone have a pick that shows how the factory mounted the power booster?