SAW THIS AT O'RILEYS

20w50 is the best protection for hydraulic or flat tappet(pre roller) motors. It stick to rotating parts. It was the oil that all motors ran in drag racing until the early 90's. Yes, PS cars run 0w10 but they get torn down often and they need to make every possible HP and have big budgets. It doesn't make much difference until you are under 9.50. Just get the motor warm if you are at the track and your car will be consistent. Don't know about the high end road race cars but the rest run 20w50.