The 340 is out....again.....

RAMM said

This is true^^^ OP it wasn't the cam bearings that caused your problem. I've used these two cam bearing numbers with reckless abandon over the years and never observed a lower end problem. With that being said I have had problems when the main oil feed wasn't drilled completely in mains 2,3,4. Might wanna look at that. J.Rob

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I don't want to read the entire thread again so maybe the OP will jump back in and answer this.

I can buy the oil holes not being drilled, or partially drilled BUT I thought the OP said this was a running engine he rebuilt. The only possible way the oil galleries not being drilled would be if the block always had these issues and the OP bought someone else's problems.

I didn't realize there were two widths of cam bearings. I don't have a durable catalog here but that's all I've ever used and I don't remember two numbers in that catalog.

I'm not a big fan of using a narrower cam bearing to save power. As the spring loads and RPM goes up, taking away bearing area is the wrong way to go. Who knows, maybe they were used to save fuel. You never know.