The Tillotson Fuel Inlet/Check Valve Gasket goes below the fuel pump diaphragm.
If your gasket is above the diaphragm this will cause tuning problems and hurt the performance of your carburetor.
16B-253 OE Tillotson High Volume Fuel Pump Gasket fits all High Volume (Double Stack, Alky) Pump Plates.
Gasket is .020” Thick