After warming up the 273 in a ‘67 Barracuda it wants to bog down real bad with a quick opening of the throttle. Tried moving the timing but no real difference. Tried moving the accelerator pump with no real difference. What does seem to make a difference is to partially close the choke valve. When blipping the throttle there looks like a ton of fuel going in and that little engine sucks a lot of air. This engine sat for many years without starting. Carb is rebuilt. We can’t tell if it is getting too much air, or fuel or both.