(2)450 DP's vs (2)750 DP's
IFR .032 in the lower position.
IAB .070
Main Jets 55/62
MAB 35
PV 9.5
PVCR .082
Under light acceleration it gets a little lean. I can hear and feel it (just a little flat). It’s not super bad 15-15.5 AFR but would like to look into it. (IFR,TSR?)
It sounds like the TSR is too big to be doing any restriction. You set it up in case its needed, so no issues there. I'd leave it alone until the other possibilities have been explored.
If it feels flat and you think its lean, stick some wires in the IABs. Change nothing else.
See what it does. ABAB or ABBA to be sure it wasn't a difference of cold vs warmed up.
Also at say 45mph+ cruise it trends upwards a little lean for my liking. Believe that’s about where the transition is tapering off before the mains come in. (IAB,MAB,IFR,TSR?)
Is it pulling? is lightly fluttering?
Might as well check the 45+mph cruise with the restricted IABs while they are in there.
At 65 mph, if it was the idle/transisition, then a change in IAB should have no effect.
And at a steady cruise anytime after 40mph I can hear an exhaust pop. I can’t feel it or see it in any of the gauges and I haven’t pinpointed any particular rpm, but it is kind of annoying to listen to. (Timing maybe?)
Maybe timing or could be the mixture. Did you make any changes since 2021?
Doesn't sound like a backfire right at the exhaust valve.
There's unburned HC in the exhaust, and someplace in the exhaust is hot enough to set it off when a bit of O2 becomes available.
In theory steady cruise should be low density and relatively cool chamber so look at vacuum advance plus the mechanical timing.
What I'm saying is yes it could be too rich, or it could be correct but not reasonably completing combustion.
I'd work on solving the idle/transition first and then come back to this.
Maybe an Aside, but my gut feeling from working with single 4 bbls is .035 MAB is large for a 55 MJ
So that would be a second path to explore.
(Even though you know I prefer making MAB adjustments only after seeing the AFR shape for the top half of 3rd or 4th gear at full throttle)