bad orange ignition box or distributor??
I doubt it's the dist. pickup at high RPM. Seems to me they give trouble typically at start/ idle.
Did you check the .008" gap at the reluctor/ pickup?
You can take your multimeter, and on low AC volts, hooked to the disconnected dist. pickup, you should get 1 volt AC when cranking
What is the voltage at the dark blue with key in "run" engine off?
You checked coil/ plug wires for continuity?
Last, sounds like you are running the vacuum at manifold vacuum,, generally you want what's called "timed" or "ported" vacuum, which means off a fitting on the carb for that purpose, which will have NO vacuum advance at idle.