Our COPO Chevelle went close to 200K miles the first time around on the regular oils of the day. The engine saw 7200 rpm a couple of times and more 6500s that I car to think about. When I tore the engine down the bearings still looked good and the pistons slid out of the bores without ridge reaming. The oil was changed regularly and most of the driving was highway. At 2000-3000 miles a year, I'll be dead and gone long before any of the engines in our old cars are worn out, no matter what oil we use. I use synthetic in our everyday cars due to the miles that we put on them. In the old ones I use synthetic in some but am not convinced that I need it. It can't hurt though. It's probably a little extra cheap insurance.
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Chevelleless after 46 years......but we did find a low mileage, six speed, silver 2005 Corvette. It will just have to do for now.