[mdross1]

This is always a hot topic in any forum.So many are certain they are running the correct viscosity oils because they might have been told it would or they truly believe if it works in this engine it has to work in mine.

No doubt they will get away with their choices but for their engines best protection especially at startup and in their unique climate (Northern cooler Southern warmer). The other things to consider are camshaft choices flat tappet or roller, tight tolerances or loose.

Finally the engines efficiency, tight tolerance lighter viscosity loose tolerance higher viscosity