Just finished another attempt to get the number. I thought I was just looking for a string of eight numbers, but there appears to be more.

The last eight look like "9B101795". I will try and get back at it with a wire brush again when able, but the engine is still in the vehicle so its hard to jet a clean shot of the number.

The engine is currently installed in a 1979 Ramcharger that I purchased from a California seller. It is obviously non-original because of both the casting date and the fact that 340's were not offered for 1979 Ramchargers.

The seller told be he picked up the engine at an Oregon/California race track where car owners pulled original engines out of cars to swap in big blocks for racing. Apparently they just dumped the engines. If so, I would imagine this was in the early 70"s, but I'm just guessing at this point.