LSX 438 Twin Turbo
#503
#508
The bottom line feeds only one of the external pumps. The main external pump is feed by the intank pump he already has. The first pump will power his truck to around the 700-800 mark before the second pumps needs to come in. 
Rick

Rick
#509

Ok, there is a main external pump and a secondary. The main is feed from the intank pump which you see from one of the pics. The second is a gravity feed setup. Both pumps have filters and check valves to nothing flows backwards. They both tee into a single line up ahead until it is brankched off to the rails where it feeds the front of the rails first. Then on the back of the firewall there is a regulator which flows back to the tank with the pic of the -8 line dumping back into the tank.
Rick































