Alternator for 1967 GMC V6 351e

[GJB]

More fun along the way of restoring my 1967 GMC Camper Cruiser. Found out today that the alternator that was in the truck, that I specifically had rebuilt by a custom rebuilder was the wrong alternator. That being the case I am now looking for a new core to rebuild or one that is already rebuilt. Problem is I don't exactly know what I am looking for Part number. Build sheet lists in box 13. as (Alter. 0693). Any Help is Highly appreciated!