I have been using the Valvoline Racing only oil, it has the Zinc pkg. in it. I checked with Huges Engines, they approved it. They stated that it had zinc at 1200ppm. The main reason for the zinc being removed is it will clog the cat. converters. If is a flat tappet cam, you better be using oil with the zinc, or an zinc additive. You can run just about anything in a roller camed engine. I use Mobile Syn. in my late model stuff. The Valvoline can be purchased at NAPA Auto Parts.