440 six pack problems and question

[Paul G]

Once a month our club has a tech session. A new member brought his 70 'cuda recreation, 440 six pack, 4 speed car. Not the original drive train.

The engine runs but has stumble issues. Not getting too deep in to his set up, first thing we did was made sure the linkage was not binding. We found the outboard carbs will try to pull open when just blipping the throttle at idle. He said the center carb was rebuilt a while back.

I would not expect the outboard carbs on the six pack, since they are vacuum operated, to try to open when blipping the throttle at idle. Like what you would expect the secondary's on a Holley four barrel to do. We pulled the vacuum line off the center carb and the outboards stayed shut when blipping the throttle. Not sure if the outboard carbs vacuum line is conected to the correct port on the center carb? Anyone have a picture or description of the correct port to connect it to?

When adjusting the idle mix screws on the center carb, it seemed to be reversed. Turning the screws all the way in had little to no effect on idle, screwing them out seemed to cause a lean stumble. Backwards of a traditional holley four barrel. Is that normal for a six pack center carb? 

[charger1972]

Sounds like its hooked to the timed vacum for the timing advance . The two ports are pretty close together, i could see them getting mixed up.

[charger1972]

You can see how close together they are. If i remember correctly , the top one is for the advance .

[Paul G]

The top port is where the vacuum for the outboard carbs is connected. He has no vacuum advance can on the dizzy. Not really an issue as far as I am concerned, vacuum advance is for economy.   

[charger1972]

Hard to find a good picture but , the top vacuum line is for the advance. So the port below it is for the outboard carbs to tie together.

[Paul G]

Thanks guys. So the secondary carbs are connected to the wrong port. I will let him know that. Of all things this guy lives in my subdivision. Never been to his house. I think I will ride down his street and, if he is out, pay him a visit. Thats what Mopar guys do I guess.

[70sixpkrt]

Here's a pic of mine with no vaccum advance. The port unplugged is for the valve cover breather