I seen in a magazine years ago something about this...but I think it was around the head or something...it was an OPEN WHEEL magazine and was a Sprint car engine(runs on methanol) can't remember the reason. I have had a couple of 11 to 1 cr 400's in street driven cars and neither ran hotter than 180.Never ran high compression though....In my opinion there is a myth about 400's running hot.. jmo