I do not own a temp sleeve, warmer, blanket, or whatever they are called. I have a clocked engine and its been run rich for long enough. Bought break in service, and have run a gallon threw it running temps no higher than 250 max. Tonight, I let my clocked engine eat! Max 298 for temp, I turned the high idol screw back out the half turn I took from it, it still run strong! Preheating, to what temp will help me elimanate warm up laps?