Have 454 I know was never in car. Used to pump water. Has K78 block casting date and is double stamped T12089ZA and T12089XJ on the front pad. I decoded the 9XJ as marine. I can't find 9ZA though. Also it seems this was from the T plant and I thought the dates of assembly were Jan2078 which doesn't fit the K78 block cast date. What's up and where I'm I going wrong?

T=tonawanda engine plant
1208=Dec 8th engine asembly date
9XJ= 79 or 89 marine 454
I do not find a 9ZA either.
K78= Nov 7th '78 or '88 cast date
Cast number may help to determine which year

Edit: I did find a 8ZA but for a 79 427 Marine and 0ZA for 80 427 Marine. The use of an 8 for a 79 looks out of place, I would think a 427 in late 70's would be a tall deck engine?