BruceH
BBB Big Bore Boss 322
Explain why the 5.0 is spec'd for 5w20 and 5w50... same motor. Exactly, 5w20 is only for CAFE. I've personally not seen much of a mpg loss running 5w30 in my 5.0.
I just don't believe the cafe thing, never have.
I could guess why but it would only be a guess. My guess would be the 5w is for the tight clearance and the 50 is due to sustained high rpm heat. It's meant for a different role than a daily driver and the sustained high heat of road racing would break down all but the stoutest oils. Does Ford spec the Motorcraft 5w-50 for it like in the GT500? Maybe Ford could answer your question?
Edit: Do you run 5w50 in your 5.0?
