3970010 is a '69 - '80 350 or a '69 327 Industrial engine, or a '69 302 Z28 engine. Could be either a 2 or 4 bolt. The casting date is April 22, 1978. It cannot be older than that. I am 100% positive about that. Being a late 70's engine, I'd have to guess at it being a low perf 2 bolt "smog hog" motor, but there are exceptions. What are the head casting numbers? Pull off a valve cover and you'll see them.
