My 1st guess if choking keeps it running is a vac leak, but since you are having problems under power as well I'd guess something else.
For sure check the timing, anywhere from 0 BTC to 16 BTC it should idle just fine without the choke. Beyond that check the whole curve, but if it is acting up, just rev it a bit with the light on it, and anything between 20 BTC total and 40 BTC total it should run and cruise and accelerate fine.
My guess is that something in the carb is messed up - either float level is WAY low, or something in the fuel circuit got dirt or a gasket or something lodged in it.
WHich carb do you have?
Rochester B or BC or BV?
Carter YF?
Or the dreaded Rochester MV?
A buddy of mine once got so mad at the Rochester MV on his truck he punched out his own windshield with his fist. The truck was not impressed and it still didn't start. But, he told me he did feel better.
