If you place the car in neutral, let it idle and then give it gas, does it bog / die? If not, most likely your idle is just set too low.
What is the idle RPM set to? Before going to crazy with diagnosis, I would raise idle RPM, and see if this solves your problem.
When you set idle, how did you do so? Did you maximize vacuum (if so, how much do you have)?
If timing is good then it is most likely a fuel issue - either too rich or too lean. From my limited experience, if the car feels like it bogs as you roll the throttle, then you are running to rich. The best way to tell is to log AFRs and see.
1965 GTO Convertible 3 speed tri-power drum brakes originally
400 cu in with tri-power
4 speed Muncie