1974 340?

Interesting. 2536030 is a 67-75 318 casting number. Boat motor?
That's what I'm thinkin'. Chrysler marine kept using 340s for a couple years after the vehicle divisions quit. I would think Mopar had to keep 340s in stock for warrantee purposes for another 3-5 years or so after discontinuation, and Direct Connection had the bare blocks for years...