If you look at the web link I gave you, it will show exactly where those numbers can be found. You need to read all the pages. Yes, the date code at the back is often hard to find because it is in an area that catches a lot of grease and dirt. So look for the block casting number, which will narrow it down to just a few years.

Then get the cylinder head codes of the center exhaust runners. That will help narrow it down too. If the heads have a number and letter, like 4C or 5C or 6X, also look for a stamped number on the leftmost vertical rib. Hard to describe, look at the pics in the article.

The intake casting number and date can be deciphered, but it is relatively meaningless. It's not a '67-'69 intake.

Most of us on this forum started working on cars before forums like this were available. You have a lot better access to information now. I had to go to the local library and order service manuals from the county library to get info like I post on my site.