I have read several engine reviews where the head goes to 320o+ and feeling good according with the reviewer. I like to read the Andrew Coholic reviews from FlyRc because of the tools he uses to measure the heating of the head and the exhaust, I believe that they are very accurate regardless of the performance of the engine. As a magazine review, every engine test is a top one, and a must to have, but you have to read between lines to really know how the engines will behive.