fryfly: Remember that Nascar engines are hand built and the internal part clearances are totally differant than our RC engines. I have to agree with many that say do not use the synthenic oils until the engine is run in somewhat with a good brand of fossile oil. Then go to the Amsoil type lube. Captinjohn Forgot to add... Diablo has a REALLY good point there. 32-1 lube has a real important advantage.... Lean run is not going to damage egine as much!