Hello. My name is Brett and Im new to the club. I am putting back together a motor and having issues lining up water pump and crankshaft pulley....off by about 1/4". The old pulley blew off into the bushes never to be found so I could match up. 

Any insight?  Thanks inadvance

Unfortunately, I do not have any information on your pulley but hopefully one of the other guys will be along soon who can answer  

Welcome to FP.

I'd reach out to Frank's Pontiac Parts and see what they have on hand. I'd be surprised if they didn't have pulleys for a 389 or 421.

https://frankspontiacparts.com/

Not using a Chevy water pump pulley are you? That will give you the difference you mention. If you had the A/C pulley and spacer on the crank, and didn't put it back on, that will give 1/4" the other way.