Block Off Plate Mechanical Fuel Pump | Holley 12-813 Holley Mechanical Fuel Pump Block Off Plate | 12-813 Designed to cover the fuel pump mounting hole in the engine block when converting from mechanical to electric fuel pumps. Mechanical fuel pump mounting pad cover Covers mechanical fuel pump mounting hole Fits Chrysler V8 small block and big block engines Fits Chevrolet small and big block engines Fits Ford small block engines