I've got a build pretty much like original poster myself and have similar pressures via stock replacement pump. Decided to run 20-50 as the car is summer weather toy anyway. Pressure now stays at 20 psi min and up to 55 or 60. On the side clearance issue, I've built a bunch of industrial diesels with GOBBS of side clearance from the factory, so it's not a huge pressure loss as ya might think.