Need help decoding a small block

[Jeffh]

Pulled it out of a what I am fairly sure was a 67 Chevy 1 ton. Might have been a '68 I wouldn't be able to tell the difference if there is one. "Supposedly" was the original motor. Casting number 3896944 which my book says 62-66 283. Date code on back of block appears to be K23 with either a 6 or an 8 for the year. Front suffix is a clear WA which my book says '65 283 or a '68 307 or a '69 350. I think I can discount the '69 350. But why no WA for '67 283 which I am fairly sure it is. I realize some of these codes and casting number books are a little messed up, does someone have a book that is the final word on whats what?