Inliners International Forums General Discussion Engines Need casting # help

some folks put a lot of faith in these casting numbers, and the stamped numbers on various engines. While the stamping number should be a pretty good indicator, it too is too general to be a last word.
I have looked up many chevy engine numbers on engines that I have bought out of an engine pile at a bone yard not knowing what they came out of. My present 292 which, I was told, came out of an '80 4X4 pickup has casting/stamping numbers just wont back that up. The numbers are just too general. I have not seen many 292 engines and my only means of identification is to look for the tall side plates, and if i can remember, the fuel pump/motor mount placement.
MY 292's block number is 3921970 which makes it a 1963 thru 1990 (according to leo's book) that really pinpoints it-right only a 27 year spread? Further, the date code is F248 meaning it was cast on June 24, 1968, or 78, or 88 now that hones it down to only a 20 year spread. The stamped FO711BG tells me on July 11 of some year at the flint engine plant is when and where these numbers were stamped on that pad. I have not taken off any pans or other sheetmetal, so I cant testify as to any timing gear oiling methods, or etc to maybe confirm or narrow down to which decade this engine belongs.
As FF said the 4.8 is probably a good bet that it is a 292, as is the motor mount locations. But good luck on which year. Any educated guesses on mine? or if it really came out of a '80 pickup hmmmm maybe it came out of a COMBINE.