It’s NOT the Evans. Bet on that. You could run 100% straight antifreeze and the thing shouldn't overheat.
Just plain rediculous to blame the coolant. Why Evans is saying that, I can’t say. But I called Evans BEFORE I bought one part for my cooling system. I run 11.28:1 compression on pump gas on iron heads without detonation. Going to 11.6ish:1 when the head gaskets get here, and don’t expect issues. One reason I can run the CR that high is my coolant NEVER goes over 175, on Evans.