318 pulley mistake, need the correct size.

Ant said
5 7/8ths dia will should clear the crank pulley and the depth is the same. So it seems like it should work, but why is listed for a 340 non A/C car? Are the water pumps different? IDK, but maybe I could make it work.

There are 2 different water pumps.
6 Vane = A/C pump (smaller pulley)
8 Vane = Non A/C pump (standard pulley)