I have to respectfully disagree. Some early 80s production blocks used this casting number. Pad below the head, the letter immediately before 318 looks like a poorly stamped M, for the Mound Road engine plant. Check just above the oil pan rail on the passenger side towards the front. I bet you'll find a partial VIN there, which would not be there on a warranty block or parts counter block. To be completely honest, this engine sounds identical to one I pulled from a 1982 Diplomat police car in the mid 90s. 360 heads, same block casting number, traces of orange paint probably from an inspection mark on the back of the heads, and it even had a 2bbl intake on it. I don't remember who I sold it to or where they were from, but this thing sounds WAY too familiar.
