Originally Posted by Larry Myers

Howie, As I recall, 12.

However, after pursuing the posts in this thread am reconsidering my analysis vs. change protocol While I have complete confidence in oil analysis am now having difficulty overcoming the ingrained habit of simply changing oil.

So, for the upcoming season have decided to revert to my old ways and change oil after every other event. Lub oil is the lifeblood of any engine so it behooves one to keep it as clean and fresh as possible. Especially in my case in that am getting ready to spend a great deal on money on my engine.

Originally Posted by Hib Halverson

If you're going to continue to use M1, I'd go with a 5W40 over the 0W40. If you're going to keep using M1 but you're also concerned about your low oil pressure, you should review the mechanical condition of the engine to see if there is a problem with is causing low oil pressure or swtich to an even higher viscosity M1 such as 15W50.

If you're going to switch, I'd try either the Red LIne 5W30 or the 10W30 or try Driven LS30 (5W30) and evaluate your oil pressure and temperature. If you still are suffering with 40 psi at high rpm and high oil temp, I'd either review the engine's mechanical condition or go to Red line 5W40 or 10W40 or Driven DT40 (5W30)

lastly, on the ZDDP issue, it is true that Red Line and Driven oils have elevated levels of ZDDP, but typically, with roller cam engines, ZDDP content is not an issue like it is with engines having flat tappet cams. In short, you don't need to make ZDDP content a key determining factor in your choice.