Changing Piston Rings in Car

^^^ This..... he already says the cylinders won't hold compressed air; but that is a subjective check without an actual leakdown gague. I would want to visually see the ring and bore conditions with this low a compression, and measure the bores. Hard to say what went wrong; ring stagger and no PCV would not seem likely at all. Either the rings are ruined (wrong gap and they seized for a moment, or re-used pistons with worn grooves, or upside down, or busted lands/rings due to detonation), or the bore surface is ruined. Or they did not bore it and there is a lot of taper and wear in the bores. I had the same level of compression as you have on #1 cylinder of a /6.... needed to bore it out to .040" !

As for stock rings, Hastings makes some good rings with a moly faced top ring. They have grit recommendations in this link:
https://www.hastingsmfg.com/ServiceTips/cylinder_bore_refinishing.htm