Setting Flathead Camshaft Timing

I need to reset the camshaft to crankshaft timing on a 59A engine with 1949 Mercury crankshaft and a Harmon Collins cam. There's a timing mark on the camshaft gear but I can't find one on the crank gear. Is there a way use the key slot on the front of the crank as a subs***ute for the mark? Also, on the engine drawings I've found it looks as though there's a toothed washer that holds the camshaft gear in place on the cam and provides a means of indexing the cam one tooth at a time with the engine front cover off. Or is it necessary to move the crank gear out of mesh in order to re-index the two gears?

Thanks for any help you can provide.

 

The keyway up top in center line ,It should be a TDC your mark should be 12 oclock.If you have the cam specs the exhaust should be little past TDC.So if its 4degs ATDC AFTER the exhaust should be just closing.Turn the crankshaft clockwise,So when piston is at bottom the exhaust valve will be open and at TDC little past the valve should be closing.It takes 2 full turn for one cycle.

 

Thanks for the info. I believe what you're saying is that if the gear had a mark it would line up directly with the keyway. Am I understanding correctly?

 

Yes some times they are marked on wrong side.