Hey trekker, did you ever figure out what it said on the block? I thought one of my blocks was a 20r cause it was in an 80, so I pulled the head to use on mine and noticed it was a 22r head, so I'm hoping the block is too. I'm not sure cause the block tag is smooth and just has ATK stamped in it. I'm hoping it's an atk 22r cause they're supposed to be pretty good engines.