Copy what Barry said. The plateau is important. A proper hone job is really important. I have tried and seen tried all kinds of ideas since the mid ‘70s. For racing, we used to make them super slick back then, almost like a mirror, and always with a plate. They would seal instantly, and then 35-40 runs later they would slow down and start leaking. Back then street stuff got a rough hone, and cast iron “quick seaters” on rebuilds. Sometimes that worked……….for 25-30,000 miles and that would wear out. Over time, the plateau caught on, and there are many methods and opinions like Barry said. The general idea is to make it rough to hold oil in the cavities, and then come back and light load it, often with finer grit, and put a slick “top” over the rough underneath. Slick for the rings to ride on, with oil in the ditches to lube the ring and help make a seal. Taper top to bottom is critical. It can wear into a “not so round” hole over time, but taper will wear the piston and the bottom of the ring out, as the ring is constantly being squeezed and expanded as it goes up and down the bore. A straight and round hole will make more power and live longer, hands down.
The definition of “straight and round” and the method of making the plateau are what makes or breaks it. If it ain’t round, never put synthetic oil in it until it has many miles on it. It won’t “wear in”. If it is round, still don’t put synthetic in it right away.
I have one Stock Eliminator engine running as good as it ever did with about 800 runs on it. That never used to happen. Modern ring machining, materials, and surface coatings are light years ahead of old tech. You can buy $50 rings or $1500 rings and to some extent you get what you pay for. The plateau also keeps the ring from wearing or burnishing. Two things that are important in my shop are valve jobs and ring seal. Those who say “there is no power in a shortblock” are missing something………and it isn’t just power. They need to run strong and run LONG.
