I ran Pennzoil 25/50 Racing Oil this season. Good oil pressure (80 psi cold and 35 psi hot at 1000 RPM). I run Alcohol so I change after very weekend and, of course it is milky when I change it. The heat stayed down (150 in the box and 185 at the end of the run). I will stay with this oil next years as it's reasonably priced at NAPA.