Jerry,
how would they run with that much wear and still hold some pressure?
As long as the oil pump can supply more oil than the bearings leak away, the pressure will stay above minimums. I've intentionally built engines with .003" clearance to let 'em wind up quicker off the turns. We would just install a high-volume pump to keep up with the leakage, and run 40 or 50 weight racing oil. Federal-Mogul used to make wide-clearance racing bearings just for such applications. Since they were for intentionally short-life engine applications, they didn't put the tin flash coat on the bearings, and used a harder alloy on the "soft" bearing layer. A "high-mileage" race engine would have less than 1,000 miles on it when we pulled it down for a rebuild.
Jerry
