Steel Weld-In Mounting Boss for USCAR (Factory Style) In-Tank Fuel Modules. These weld-in mounting rings allow the use of a modern in-tank EFI fuel module in your custom or modified fuel tank. Most late model GM, Mopar, and Ford factory fuel modules have been standardized to a common size with a thin 6" diameter hat at the top of the fuel module. Choose from aluminum, steel, or stainless steel mounting ring for easy welding (use same material as your fuel tank).. Requires Welding to Fuel Tank or Fuel Cell._x000D_ _x000D_ Use w/ GM Locking ring # 10325852 to Retain Fuel Module to Weld-in Boss.