before I honed, the groove was there, even deeper, and the engine was burning a quart of oil every hundred miles. But the rings in 5 of the cylinders had a lot of wear on them, too. It was not fouling any plugs. It sure will be interesting to see how it works when it's done! At the very least, it's a cheap experiment. And if it goes 200 miles on a quart now, it will use half as much oil, which is a significant improvement--it will only take two cases of oil for a long trip, instead of 4. I did that Corvair a couple years ago, it had two bores with serious rust issues, one of them had an area about 2" x 2" rusted away. It used a quart every 50 miles. I replaced the two bad cylinders, and put in new rings, and it went down to about 500 miles per quart, which I hear is about as good as you can expect from one of those.