PPE DURAMAX CP3 PUMP 3/8” INLET FITTING. Get the most fuel flow possible from your stock CP3 pump by eliminating possible cavitation damage to CP3 pump from excessive suction required by high pressure CP3’s fuel injection pump with this “high flow” PPE CP3 Pump Inlet Fitting. The key is the larger inner diameter of the PPE fitting, which allows fuel to flow 70% more efficiently than with the restrictive stock 1/4 inch inlet fitting. With a greater volume of fuel available to it, the CP3 injection pump will be able to perform at its optimum capability.