My boat has three big blocks. I still run solid flat tappet cams.

A few years ago, about 15 hours after changing the oil (5 gallons per engine), I wiped all three cams within an hour of each other. So badly that I had to take the lifters out the wrong way in some positions.

Made no sense to me at the time. Lo and behold, I discovered about half of the zddp was removed from my "racing oil" because of EPA regs for catalytic converter fouling caused by zddp.

So now I use Rotella T and a quart of GM EOS in each engine.

Sure would like to find something cheaper than the GM EOS. I bought a few cases of the older stuff on ebay. The stealership wants about 15 bucks a pint for the new stuff.

Someday I'll build the engines with roller cams but then I'll have to change cam profiles, meaning a change in horsepower. And if I do that, I may as well go 1300 hp each with new #6 drives. My wallet won't like that....

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Thank You!
Fred
2009 ML350
2004 SL600
2004 SL500
1996 SL600
2002 SLK32
2005 CLK320 cabrio
2003 ML350
1997 C280 Sport