Like Jerry, my first suggestion would have been the electronic ignition.
Since the same symptom occured with points:
From what you have posted, by GUESS would still be distributor. Possibly a "catch" in the rotation of the plates at a certain spot, and then when it rotates past that spot, it functions. Or, as Jerry stated, possibly a missing or broken spring.
I would not guess the carburetor, for the following reasons:
"Under 1200 it purrs"
"above 1400 it really has some pep"
The idle circuit should take you to maybe 800, the idle transfer to a little more than a 1000, and then you are on the main circuit. Cannot think of any way the main circuit would be good from 1000 ~ 1200, bad from 1200 ~ 1400, and then good again from 1400 up.
Carburetors have no personalities (well, maybe Holleys
). But ignition systems do have personalities.
I would suggest a really good look at the distributor.
Jon.
