K' , I hope you figure out what was wrong with it, I figured you had checked the small ring, just seeking something to grasp at from my feeble brain cells. I have no issues with my 850 chain, but I am looking for a period correct Regina chain, either an Extra (to match the NOS freewheel/cluster I got from Scott,) or a nice Oro, if it isn't more price wise than I out into the entire bike

Best of luck, the Merckx sure turned out nice.