I broke in my tuned promo yesterday using the heat cycle method. I used a 10th scale foam to insulate the cooling head like Drake suggested and that really works. My car was spitting fuel and barely taking off and still temping slightly over 200. It wouldn't stay running on the initial startup because the original glow plug was shot right out of the box. After about 10 3-4 minute cycles, I put a moderate race tune on it and let her scream a little. I love the way this motor sounds. I'm a Nova guy so the smoothness of this engine was very different, but I know that its smoothness will actually be more beneficial on the track. The compression after a third of a gallon isn't as tight as the nova's, but in my experience with high end motors, most of them are like this but they go on to get 10+ gallons and never miss a beat. Too much compression is just unnecessarily hard on the crank pin and rod. I look forward to running this engine this season.