I would say you are making the right choice by going with o ringed copper. My personal opinion is to cut a receiver grove in the head, and the o ring in the block/ sleeve. The receiver groove distorts the gasket to prevent any straight path for combustion gases to escape.
At the level you are at, I wouldn’t do it any other way.
^^
That is your answer. Good copper gasket. I had my Indy block done and receiver groove in the heads. .043 wire. I will see if I can get specs as to depth of the oring groove and receiver groove for you.
Cody
