Thanks Jim! After reading this on another site, I see that the number 2 was routinely stamped on Pontiac engines followed by a number for the year (8 in my case) and then the letter for assembly plant followed by the VIN. So, looks like I'm good! By the way Jim, I asked you a question on a post regarding carburetor adjustment.
From 1955 until early 1967, the block unit number represented the last digits of the VIN of the vehicle that the motor was originally installed in. Late in 1967, the number 2 was added at the beginning to represent Pontiac, followed by a digit that indicated the last number of the model year (such as “9” for 1969) and a letter that represented the originating assembly plant. These digits were followed by the last 6 digits of the VIN.