massive reconfiguration time again.

Ok so here is the theory that i have been told(May not be accurate for a highway vehicle.)

You should have burn or discolor down 3 threads if you have the right heat range spark plug in.

If the timing is right, should be starting around the ground bend......to about were it is now.

Fuel curve should have a light gray(depending on fuel grade) color all the way around the base ring(were the ground strap is welded on) If you don't have a fuel ring all the way around the base, you could be getting lean.

So with that said......Its to cold of a spark plug
Timing is to high and its running rich..............
The problem with a street eng is everything affects everything.
Does your mechanical curve ramp to fast(compression with a street car i say yes)
do you have too much advance in the vac canister, advance???
To much initial timing???..... need to take more out of the mechanical curve????

The problem is that plug is showing idle, cruise (fuel tranfer slot) to hill climbing(running thru the main booster), to full throttle (main boost and power valve inrichment(If it s a holley or metering rods if its not.)

I'm not the one to tell any one, how to tune a street car........but that's what i see/read on your plug......But it's for full throttle, cut clean drag racing.