Woodruff key found in the bottom of a 340 with 7qt. pan

T-Man700 said
I was debating about throwing a new water pump on it.

Make it a HD, 8-vane, anti-cavitation plated, Hi-flow version with a 5/8 impeller shaft. Mine was new in 2000, and still works like a charm. It came with the tip machined down to fit the 1/2 inch pulley and stuff.