X1 Series Internal Conversion Kit, .313 Seat (red in color), 35-75 psi. From carbureted to EFI pressures, naturally aspirated or forced induction, the X1 is designed to span the entire range of applications providing dependable fuel pressure regulation. Making the change from a carburetor to EFI or EFI to carburetor? There is no longer a need to purchase a new regulator. Simply utilize one of three conversion kits (sold separately) to match the operating range required of your engine. Replace original X1 Series regulator internals with the conversion kit of your choice and you have a regulator with vastly different characteristics. While versatility is one of the X1?s greatest assets, it is far from the only new design feature. Utilizing larger -08 AN inlet/outlet/return ports to accommodate increased flow, Aeromotive incredibly reduced overall weight by 33 percent (compared to Aeromotive 13109 regulator). Even with these new design components, none of the traditional features expected of a genuine Aeromotive product have been neglected. Still integrated is the 1/8 NPT gauge port and 1:1 ratio boost reference port for easy forced induction connection. The X1 Series provides flexible performance that grows as your fuel system grows.