So, symptom start a week ago.
I rebuild the original carb my self. Replace the radiator, put in a new bigger fan. After the rebuild, it ran good for couple weeks. Suddenly one day, it starts to bog down on acceleration. My foot not even on the gas pedal over 1/3. I can slowly work it out to reach a normal cruising speed, but it takes a longer time. And during the acceleration, it almost stall.
My engine at 9-10BTDC, idle at 750-800(Automatic car), with new fuel line, fuel filter.
So what...

1966 Mustang C-code 2V, bogging down on acceleration