NITROUS has the S&P modded early style fuel rail that has a return line. He said the instructions were incorrect from S&P and he had the hoses reversed. The fuel feed comes from the pump into the rail and then the regulator bleeds off excess pressure back to the tank, as it should. The way it was plumbed, pressure would hit the regulator and go nowhere. Even if it made it past the reg from the feed side, the bled off fuel would just run straight back to the tank without resistance.