Funny you mention that. A local guy to me and a very good friend of the guy I worked for stopped by the shop one night after I’d gone home, and he saw my junk on the stand as I was mocking it up.
I didn’t know this and the next day he went to lunch with us. He started telling me back in the early 1970’s they were having rod bearing issues, and Chrysler gave him some money to try and find a cause and a cure. I suppose others were given money too because it is an issue, but Jim was a sharp cat, a multi time National Record holder in NHRA and AHRA so he had some whiskers.
Anyway, he tells me they discovered the issue was the sharp corners where the feed to the mains was drilled into the main oil gallery. They made some kind of mock up so they could watch how oil flowed over holes like that, found text books on fluid dynamics...spent some real time researching the issue and trying to learn the dynamics of the problem.
So he says once we figured out that those sharp corners were the issue, we had some 10 inch shank carbide burrs made up. There were several different burrs, with slightly different shapes and three different sizes IIRC, so they could get on there and put a chamfer as best they could on the square edges.
So I’m thinking WTF?? If Chrysler was paying for R&D on this issue and this was cute, why wasn’t a tech bulletin sent out or something. So I asked him if a tech bulletin was ever released on his findings and I’ll never forget his answer. He said “oh hell no...it didn’t make a pinch of **** difference”.
A few days later he stopped by with the burrs. Interesting stuff. But he said those square corners didn’t matter.