Synthetic Oil Improvement in /6

1970Duster said
^Regular oil with additives.

Yeah, more than likely thats what I will be doing for now.

1970Dart198 said
I don't think its all synthetic, Brad Penn does it the old-school way. The higher amounts of zinc will protect mechanical lifters from corrosion newer oils won't.

Now, i'm not going to be a salesman for them, nor do I believe they make the best oil product around, but they are good at making oil for older motors, they market to muscle-car-era owners. (Although a slant 6 is hardly one!)

I'd go with the 10w-30 #7150 for everyday driving, but at $12 a quart, it must be as good as synthetic for top dollar!

Wow, I honestly didn't know it cost that much! Thats a bit high. But then again, I guess you get what you pay for.

nm9stheham said
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.

Mobil 1 will have a thinner actual viscosity in all temps for the same viscosity 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 original 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 experience 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

I see your point. I ran synthetic, and yes it did cause some small leaks in my wife's old Xterra.
Now her new 2014 Jeep, synthetic is just what came in it from the factory. Or maybe a blend, I can't remember. We have only had it a month.
I just bought this B body with a 225, with 93K on it. I honestly didn't know they went that many miles. As you stated you had one with many miles on it.
When I build my 440 over the next year to slip into it.
My question would be, with a clean rebuild, and all new updated parts. Would it be considered a motor that still needs high ZDDP? Or run the synthetic right from the start?
I sure hope that made sense...