STPs label once read THE RACER’S EDGE. Well, racing engines are LOOSE engines. The clearences for pistons and bearings are very loose and require a great volume of oil and a thicker oil. Late model engines are built to very close tolerance with very tight clearences which call for thinner oils. I have seen Japanese engines fail to run when temperatures dropped below 10*F due to thick oil pumping up the lifters, preventing the valves from fully closing. Also,when tearing down a seized 4 cylinder Ranger engine one cold January I found the oil pump drive shaft twisted into a cork screw and lying in the pan. The driver used 20-50 oil and one of the molasses additives.