I ran a '54 Customline, with a 312 I put in it, for several years. When I switched to a 'C' cam, the engine was already in the car. I 'invented' a tool to replace the nailhead lifters while laying on my back and weaseling them past the crank. Had my brother clip clothes-pins on, up in the valley, to hold the lifters in place until they were all in and I could put the cam in. Had to remove the grill and radiator to get a long-enough shot. We were working in the back yard with a flashlight to see with. Ultimately had the factory 'race' dual quads and a Paxton blower. It, too, was designed as a race unit and the part of the front of the casting intended to house the boost-limiter was simply left unmachined. The impeller was also significantly different.
The fuel pump had to be boost-registered, requiring modifications that sent blower pressure from one of the carb hats to the back side of the pump diaphragm. Thus, as the pressure went up, the fuel pressure went up as well. At idle, fuel pressure was at about six pounds, but when I had my foot in it, the pressure gauge was pegged at 15 pounds. Great fun on Telegraph Road with the 421 Pontiacs and 409 Chibrolays.
KS