Decode G440 engine

Hi, first timer here so I apologize as I’m sure this has been covered. I have a G440 HP block/engine built and runs. Had it 30 years. I was told it was a 6 Pak engine. How do I further decode anything about it? I bought the transmission at the same time from the guy also. Thx for any help.

View attachment 66640
Author: Tom Anderson