HFPs dual pump assembly for 99-02 LS1 F-bodies starts out with an OEM float tested assembly. A Phenix Industries (made in America) -8AN outlet fitting (can be substituted for -6AN) and a -6AN return fitting are used to deliver fuel to the motor, and back to the tank. [2] HFP-255LPH vane impeller pumps are secured by our custom TIG welded fixture. This is NOT a floating pump setup where the pumps just sit inside and pull on the hoses. A corrugated high pressure flex hose is used to connect both pumps after the y-block up to the top of the assembly. ALL OEM functions of the assembly are retained including the float mechanism, the vent, the pressure sensor, and of course the return line. Looking for a direct drop-in dual pump assembly built RIGHT? Consider an HFP-DLS1Z direct drop-in assembly. No core charge needed, and USPS Priority shipping is free within the US.