46u: It's not so much the heat of the air, but the heat from the ground. It rarely gets 100 here, but its as humid as possible being oceanside. The sand retains alot of the sun's heat and transfers it to the car. I run 20-30 degrees cooler on pavement or grass. I don't run more than 250 even on the sand, but I would prefer to run 220-230. I am looking for as many ways as possible to keep my engine as cool as I can.

Gruder: Is there a noticeable difference in the weight between the plastic diff cups and the alloy ones? Suppose I should as the same of the cooling head. I'm not looking to add more weight, a small gain I could live with. Being that it is larger in diameter with more fins, I would expect it would cool more efficiently and weight slightly more as well. They also claim 7075 alloy displaces heat better than 6065, so that should be a factor also. I'm no metallurgist but it seems logical. I suspect the 7075 weighs a bit more, too. Keep us posted on your progress.