Crank sprocket slot options

Looks like you have a Cloyes 3 key way set. They have 3 slots, "0", "4* BTDC" and "4* ATDC".
The crank key should fit in all 3 slots. I would install it straight up, 0. Sometimes you have to use a file or emery cloth to dress the key as they are prone to burrs and dings.