Your wideband is only an average of four cylinders thru each exhaust pipe. Before you go any leaner you should pull plugs and read them. You always should tune to the leanest cylinder and fatten it up, very important especially at WOT. A dual plane intake will almost always need stagger jetting to get a carb dialed in.
That's a good point. When I had the exhaust installed (TTi headers), I had a bung welded in on both sides. So, once I have it tuned to where I like it, I swap sides and check it there also. Have swapped a few times now.
But I haven't considered confirming the WOT on both sides. Thanks for the reminder. The best WOT power via the buttometer seemed to be where it would start off (at WOT) at about 12.7 or so and as it pulled it creeped to about 12.2. I swear, as it approached 12.2 I could feel it pulling harder, and sounding better.
The primary side POWER Mode and CRUISE Mode is a difficult balancing act. To make the POWER AFR safe, I will need to go to a bigger main jet because there is no smaller (diameter) metering rod than 0.037". But when I go to a bigger main jet, the CRUISE Mode gets way richer because there is no larger (diameter) metering rod than 0.077". Which is why I want to have one custom made.
I'm seriously considering buying rod stock and having a pair turned to 0.079" / 0.030" and running that in a .100" main jet. Based on my calculations, that would put me right where I need to be.