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Fuel Pump MOUNTING SCREWS -- FP-104
Since this question comes up periodically, nounting screws for teh SU Fuel pump are part number AJD6155Z -- Screw, pump to bracket -- Hex Head, 1/4-26-BSF X 5/8.
BSF (British Standard Fine) is the fine thread series of the BSW (British Standard Whitworth) 55 degree threads. All of the fasteners and fittings in the SU pump are BA, BSF or BSP. It is a throwback to pre-war design, before the Allied countries adopted Unified thread standards for the war machinery. They continued making the same fuel pumps after the war, so the threads did not change to Unified standard. The Auster windscreen frame and many of the electrical parts are also like that.