EXHAUST VALVE T100 TO 66 1.312 HEAD DIA

This is the exhaust valve listed for the T100 up to 1966, with a 1.312 in. head diameter, cataloged under 70-4013 (also shown as B56A or E4013 in older parts books). It sits in the cylinder head and lets spent combustion gases out to the exhaust port on every power stroke, so it's a wear item that takes direct heat and pressure with every cycle of the engine.