Is there an ideal temperature range for oil that will give the motor the best lubrication ? I know the basics: oil should not be too cool, nor too hot. But is there a consensus as too the "perfect" temperature ? The oils being used are Mobil 1 15w-50. And Mobil 1 0w-40 The engines are vintage Ford iron High Performance 289's and various Ford FE series iron engines, ( 352, 390, 427, and 428 ci. ). All will see some high speed endurance racing, as well as street use. any information will be appreciated. Z.