Drew's suggestion is the only way.

high-pressure engine code locations

low-pressure engine code locations

Find and post the head and block casting codes, the head and block date casting codes, and engine serial number (it was called the engine identification code in some years - there was no engine serial number on 1957 and later 235/261 engines).

The block and head could be from different years. That is why it is a good idea to get all the codes and then get Shop Manuals for those years.