[antique69lemans]

Originally Posted by gearbanger

Were the upper rod bearings cupped to the point they wouldn't stay in the rod. If so, I would say definitely detonation. I went through several engines back before I knew about detonation. Engines all ran good and you could not hear any pinging or rattling. But after a few thousand miles the oil pressure would go away and eventually would start knocking.

Pull it apart and all the bearing would be down to the copper. That was back when I was trying to run 670s on a 406 with pump gas. Not gonna work.

Bearing inserts being loose AFTER meltdown is common. They are deformed under the extreme heat and lose their shape. The rod big end is suspect from the heat. Even if they were perfect before, the rods will probably be "egged" and cause improper clearances with new inserts. I have seen oil starvation cause rods and blocks to blacken from the heat and burnt oil. I would personally consider another set of rods in the next build.