Help a fella understand Federal PS pump pulleys

Okay guys, here's an update. I got my pulley in the mail today, and it is the exact correct pulley in every way. So if you are looking for a pulley for a 225 slant six with a federal pump just like I was... your part number is indeed 2951157.

And if anyone else is looking for that pulley, the fella I bought it from on ebay has one left. I paid 40 bucks plus shipping.