Originally Posted by Blusmbl
Originally Posted by Sniper
Castrol GTX Classic has high zinc, 1400 ppm, and phosphorus and is available at Walmart for reasonable cost. It's only available in 20w50 though.


Another option is the Mobil 1 high mileage 15W50- it's cheap at Wal Mart, usually $26 for 5 quarts, and has enough zinc for flat tappet cams. I've been using it for a few years now. The other Mobil 1 oils don't have enough zinc, but the 15W50 does.


I run Valvoline VR-1 10w30 conventional in my car. What would happen if I switched to Mobil 1? Mobil 1 is synthetic.