Tuning a Proform/Holley carb, what parts and tools?

Yeah, I hear you, but yesterday I corrected the timing, fuel pressure, and float level.
The car is running great now, until third gear WOT.
It'll burn the tires halfway through second, then abot 3300 in third it just quits until I let off.
Extremely frustrating to be back to my original problem.

Unless you have a better suggestion on where to go from here, this is my plan for today-

Gonna try to rig a pressure guage I can see to check for lost pressure.
Martin suggested running my timing light into the cabin to see if I am losing spark.