The valve in my picture are alloy, that why the shaft is thicker,
The alloy valves wear off valve gear
The timing mark is the shorter spline on gear
U are lucky you valves are steel
Both valve are the same so when fitted one valve will look wrong {the flywheel side valve will look upsidedown going to the kipps chamber but both valve should line up perfect with the exhaust subports on the opened position
iF u look at my picture, broken top valve {the red marker line is where shorter spline is } and the centre chisel mark on the broken side