Lunati camshaft keyway/woodruff key?

Magnum engines did not have a snout, they had electric fuel pumps and no snout, no fuel pump eccentric...

You can go to a local Ace Hardware in the fastener aisle there is a drawer with "woodruff keys" that you can find them in different widths and lengths. If worse comes to worse, get one the right width and grind it down to the proper length on a bench grinder....