Long story... Only use - Road Course endurance racing - 7-14 hour races.
3.0 - bored .040 over
Large cam
3" cold air intake setup.
Speed pro pistons and rings
Stock 19lb injectors.

Ran a smoke test and no vac leaks.
Ran exhaust leak check and no exhaust leaks (actually there was but replaced crossover gaskets and now there is none)
Injectors are good.

Timed to 15btdc
New #4 rapid fire plugs gapped to .40
MSD 6 ignition, msd coil, 8.5 magnacore wires

New O2, Map and coolant sensor.
New FPR. Pressure after turning off car holds at 40+ for a few hours. Was a 20 after a day.
Fuel pump is walbro 190lph gsl391 external, inline pump (non high pressure - they make 2 models of the 190).
Fuel cell - feeds and returns on 5/16 lines (had it returning on 1/4 line, but pressure jumps up to 50-52 at idle - spec is 48)
14 volts to pump.

Fuel Pressure at idle is 48.
Pull vac hose, pressure jumps to 52-54
Vac at idle - 15-16 (nomal for the cam in it) Drops to 0 when burping, jumps up to 25 then settles again.
WOT, fuel pressure goes up to 50-52

TPS sensor tests fine.
O2 sensor - at car side of plug, 12 volts when checking heated + and - wires, 3.7 volts when checking bk/lb line that splices with TPS.
Car running, at warm idle (180-190) voltage on o2 signal wire is jumping from .52 to .90. However most commonly hitting .68 to .82
Burping throttle, drops to .25-35. Holding throttle at 3k, .25-.4
Unplug vac line from FPR and plug vac line, o2 sensor reading jumps up in high .80's to .90's
Unplug booster line and cause vac leak, reading drops to around .40

There is a leak at the donut which I will fix. It is after the O2 sensor, so "shouldn't" have an impact, but... I will get it fixed. I would think if it was causing issues and the o2 sensor was seeing this leak, it would actually lean out the voltage and call for more fuel, not the opposite.

Ever since the rebuild of the motor (done by reputable chrysler specific motor shop) - the plug tips are ash white. Prior to the rebuild and the engine bored at .030, they were nice and black.

So, with all of this... why are the plugs ash white. Sure seams like it is running lean, yet, overall, the numbers seem to be ok.
From the o2 sensor, it seems it might be sensing running rich and adjusting to lean out a bit, but as the numbers jump, I don't see it go under .45
With swapping out the sensors, fpr, etc... I am at a loss at to what to try next??? I have a set of 22lb injectors I could throw in, which would dump slightly more fuel, or I have a 190lph high pressure that I could try and push more fuel through the rail, but not sure either of those would be much use. Thoughts???