10. The factory 8.3L fuel rail is a returnless system. This means when the fuel reaches the end of the rail, it does not continue to flow directly back into the tank. To ensure the correct amount of fuel pressure, but excess fuel can still flow back into the cell, we used an Aeromotive 13109 bypass regulator (arrow). To finish out our fuel system, we used Aeroquip stainless steel braded -6 lines to tie-in the rail, regulator, and pump along with an assortment of AN fittings from Russell and Aeromotive.