Ah yes, the age old Oil question. This is one of those topics that's like toothpaste and shaving cream.....many people are satisfied with completely different products.....and I'll join in the fray here. Of course, use what works for you, but for ME....I've been using a straight Valvoline 30wt Racing, ( which has zinc in it ) with an additional additive ZDDP added for break-in. After break-in, I drained and re-filled with just Valvoline 30wt Racing. it's been 15 years now since I re-built the engine, and I drive it everyday back-and-forth to work, tow the ski-boat, and run all my errands with it. Here in Los Angeles California, it doesn't get cold enough outside to need a 10-30, although it wouldn't hurt a thing, I just don't need to.
I am the engine assembler at a well known performance engine shop which has been around since 1965, we do everything from very vintage restoration engines to all alloy Top Fuel Hemis to every day stock. We sell Brad Penn break-in oil as well...It's a good oil and many customers request a special break-in oil, so we supply what they want. What people tend not to know, is that many racing engines, and most newer factory stock engines are roller cam equipped, and really don't NEED a break-in oil. Do you really think John Force puts 500 miles on his fueler before changing the oil and going out to race? For the most part, break-in is for the older flat-tappet solid or hydraulic cam and lifters to wear in together, here is where zinc is needed and racing oils have zinc. As for rings, today, hardy nobody runs just plain old cast iron rings like the old Flathead Fords and Stovebolt Chevys came with since possibly the sixties. Most overhauls, even conservative re-builds will use Moly-faced top rings with ductile iron seconds, and these will seat in quickly. So there isn't really a need to pay more for a special break-in oil ( you're going to change it in 500 miles anyway aren't you), but if you'll sleep better, it surely won't hurt a damn thing. As for multi-grade weights, you be the judge as to your existing climate. New cars with tighter clearances require multi-grades. Finally, Synthetics....synthetic oil doesn't break down like a mineral oil may after a time, but changing the oil isn't just to rid yourself of broken down oil, changing oil is to get rid of whats now mixed into the oil. Moisture, carbon deposits, fine particulates not caught in the filter continues to be trapped in oils, even synthetics, and I'd rather change my oil more often than brag about how many miles I have on it. In Aircraft School, we learned that here in the U.S.A., the FAA mandates a mineral oil be used for internal combustion ( piston ) engines, and only certifies synthetics for turbines and gearboxes, where the synthetic oils do not come into contact with the combustion process. Food for thought. Although I know many people swear by their synthetic oil, I'll stick with a petroleum based oil...but then...it's like toothpaste and shaving cream, isn't it?