PISTON STYLE FUEL PUMP Revolutionary new design in mechanical fuel pump technologyOperates on a totally different principle than conventional diaphragm style fuel pumps Available for SB Chevy The reciprocating piston, which operates off the standard fuel pump rod, only requires 25 pounds of force compared to the 125 pounds needed by a conventional diaphragm style pump. This pump operates at a constant 4 to 50 PSI when used with most aftermarket fuel pressure regulators. (Note: This pump cannot be used without a regulator.) There is absolutely no drop in fuel pressure over the entire rpm range. Can be used with gasoline or methanol. Can only be used with carburetors with EFI style coming soon. The Piston Pump only flows as much fuel as required.