The thicker and cooler the oil is the more power is gain by getting it hotter, 10W3Wt gained 3 HP from 120 F oil temps going up to 170F oil temps, if my memory is accurate still luck
5W20WT no change in HP with cool or hot oil work shruggy

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)