Oh no! Not another thick vs thin,haha! Well here`s my question/s. I went down to a 10W40 from a 20W50 recently. 10W40: SILENT smooth startups,lightning fast acceleration through the powerband. Looking at the camshaft,oil bath is thinner and splashes off. Not as quiet on WOT runs. 20W50: Smoother once good and hot,most noticable on WOT........smooth as glass,but sluggish on a cool engine. Looking at the camshaft while running,oil bath is MUCH thicker,is saturated,and doesn`t fling off but clings to it completely. Soooooooo,if you like to drive it like you stole it,which oil is better over the long run? A thin or thick??????