All radiators aren't the same, the plastic/aluminum do seem to work noticeably better than the copper/brass that most replacements are. Also, I put a brand new one in a E-12 I used to have and it was OK but not great in extreme conditions but have had other copper/brass that did much better that were the same size. The 7's have a larger radiator than the E-3,9,12,24,28 that also use the M30 engine and I've had most of those models and while I had to keep on top of things I don't overheat on vacation in Las Vegas in August with the air cranking. I'd have a good (not cheapest) radiator shop check it out and go from there. Mike W.