Synthetic Oil Improvement in /6

Don't mix the issues of the benefits of full synthetic on rings bearings, bores, etc., and the zinc for flat tappet wear. You can add zinc additives to full synthetic Pennzoil, whoever). As noted and as I understand, Brad Penn is petroleum oil with additives. And for a stock engine, and their lower cam lobe pressures, I have to question if the lower zinc is an issue any way. For a high lift cam and high pressure springs, then I would be concerned.

Sorry, in all my racing, the difference in breakdown of the oil between synthetic and non-synthetic is dramatic. Petroleum based oils simply are not the same, regardless of who brands or makes it. If I could have shown you the differences I have experienced in wear and oil breakdown, you would understand that they are truly not the same thing.

Mobiel 1 will have a thinner actual viscosity in all temps for the same viscosty ratings on the label. It is just more viscosity stable than petroleum oils over temp, and does not need the viscosity improvers that are used in petroleum oils. So I have always taken that as being the reason to have more leaks. When it first came out in the 70's, there were regular reports of leaks when switching engine with high miles to Mobil 1. The only orignal weights available were like 5W20 or 10W30 tops. When 10W40 and 20W50 Mobil 1 was brought out, the reports of leaks dropped. Based on all my experince with it (around 1 million street miles and a few hundred race hours), I'll just plug any leaks as best I can and keep using it! I had a 225 with over a quarter million miles with no leaks with Mobil 1.....YMMV