Aluminum Heads ?

That's all part of the thermal issue. They transfer more heat to the oil. Truthfully, if the oil is workign right, it takes as much heat away as the cooling system does, and ten degrees should mean nothing. Typical temps are around 220-240 depending on the system, the engine, and the pan. A good oil will survive to 260 pretty easy. Beyond that, synthetics will live better. But really you got problems..lol. Again, I think they are a better option in every application except where rules mandate iron. So long as the design is taken into consideration in the design phase. But, sometimes the budget cant absorb that.