The things you can find at Estate Sales

[JMinPDX]

I usually buy Castrol 20w50 for my M10s & M30. Happened upon an estate sale near my house and found 20 QTs of GP1 20w50 high zinc racing oil. Thoughts on using it in a stock m30? At $2.00ea I could not pass it up.
It was the estate of a Porsche owner. Also found Wurth brake cleaner(2), LiquiMolly injection cleaner(6j and Motul Dot 4 brake fluid (2).

No Porsches but a nice 86 Mercedes 300e that tempted me but I did not bid on it.

GP-1 Synthetic Blend 20W-50, Gallon

Designed for competition vehicles, classic cars, and imports, with high performance engines requiring a 20W-50 viscosity. GP-1 is compatible with Methanol, E85, and high octane race fuel. Blended with genuine Pennsylvania Grade base oil, GP-1 achieves a higher Pressure-Viscosity Coefficient for...

drivenracingoil.com

 

[e30austin]

i wouldn't hesitate. your m30 will love it, and your bearings will thank you for the high zinc content.

 

[otter74]

I’d certainly have no problem using it in my M30. As the owner of an air-cooled 911 that uses ~11 quarts of high-zinc 20W50, I’d buy whatever I saw at $2/qt in a heartbeat.