casting #`s

The block casting# of 2806830-2 appears to disagree w/ your decoding of the stamped number. The casting shows as a 68+ engine in the chart of post #3 and in another source I saved. If yours has 5 freeze plugs all in a row, I doubt it is a 1965 engine. My 64 slant has casting# 2463430-8 and 3 freeze plugs, staggered, which is consistent with above table, though my other source lists 1966 (I don't know the history). All early blocks had 3 freeze plugs.