AEM’s Adjustable Fuel Pressure Regulators are capable of supporting enough fuel flow for engines up to 1000 horsepower. Our patented interchangeable discharge ports enable the regulator’s output to match the output of any fuel pump. A single large discharge orifice is included. AEM® includes a custom barb fitting to accommodate the factory fuel hose and the base of each regulator is tapped to accept a -6 AN or 9/16×18 fittings. AEM 25-300BK Adjustable Fuel Pressure Regulator – Inline Flange with Straight Return Fitting – Black. Mounts directly to O. Fuel rail or AEM High Volume Fuel Rail. Patented interchangeable discharge orifices match output of virtually any fuel pump (single large port included). Adjustable from 20 psi to maximum fuel pump capacity. Boost dependent rising fuel pressure rate (1:1). CNC-machined from 6061-T6 billet aluminum. Accept a -6 AN or 9/16×18 fittings. ATV, UTV, Motorcycle & Marine. Audio & Mobile Electronics. Books, Literature & Videos. Engine & Engine Components. Lifestyle, Clothing & Memorabilia. Oil, Fluids, & Chemicals. Tools & Shop Equipment. Trailer, Towing & Winches.