[cabmandone]

On the plus side, you're making progress. WILD though that it would idle well on only half. My brother's carbed 3.2 ran pretty rough with just one dead. I would think as long as you have the wide band sensor in stream with both you'd read off. My car just today with something as simple as the oil fill cap off was registering lean. I noticed it and started looking around and sure enough, cap was off DUH! Put the cap on and I was right back in the 14.4 to 14.7 range at idle.
Just read your comment again and noticed you must have a 2 in setup for the exhaust. That'll do it. But it's still really surprising you couldn't feel any difference in the way it was running. I noticed my car was a bit off with just the oil fill cap missing. It just didn't sound right at idle.