I would think that BillK might be on to something here
Is this a new engine or has it run before without hurting the thrust bearing ?
The reason I ask is I had a problem with a thrust bearing in a 350 Chevy years ago. The block had been align honed and when they cut the cap they cut it crooked and it was tilting the thrust bearing just slightly. Took me a while to figure it out.
Did something change in your combination right before your thrust problem started ?
Just thinking out loud
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