Need engine ID help
 

A friend of mine has a GM 3970010 block it has numbers on the pad infront of the head . Does anyone know what this engine is from or what they mean or where I can check them. The number is K1113CNU.
Thank you for your help. Wayne

4 bolt small block.Should have a 4 inch bore. Make sure it doesn't have made in Mexico on it right near that number. Originally that number was from the late 60s to late 70s or early 80s. Supposedly a higher nickel block as denoted by the 10 but I think that's an old fable.

Not sure on the other number but I bet that one simply states how the drive train was configured in the original vehicle. ie 350 cu in, manual trans, AC.