FE crank keys

[Mbowling]

What size are the 2 half round woodruff keys in my fe crank?  The straight one appears to be 1/4”.
And why are there 2 half round keys?  It appears only one would engage the crankshaft timing gear.

[blykins]

There are two because I think the intention was for the front woodruff key to catch the balancer spacer.  However, the rear key that the timing gear catches will also catch the spacer.

They are SBC/BBC crank keys.