one sweet ws6

I run royal purple 5-30 car likes it

Firebrian

I have no problem finding M1 0w-40 at Walmart. I bought 2 jugs last year ($10.57 after rebates) that will get me through to 2019. If it should run out, there are many other choices. I don't look for 10w-40 M1 but no doubt it's harder to come by. Same for the 0w-30. The end of year AutoZone clearance sales at $2/qt often cough up supplies of those grades. I bought several jugs of Castrol Edge 0w-40 for $10 each last December at AZ and just sold it at cost as I didn't see myself ever using it. I had a dozen quarts of PP 5w-40 Euro (A3/B4) at $2/qt that I also just handed away at cost. That's a solid 40 grade oil.

Last I checked, the M1 10w-40 only comes in High Mileage variant, hence it's really thick for a 40....45% higher viscosity at 100 deg C than Mobil 1 5w-30. I don't see a need for anything that stout in a stock/lightly modded LS1.