67 Pontiac Bonneville-Part Replacements

Bonneville Specs:

Engine: 6.6L, 400 CID, V8, w/AC
Transmission: Uncertain
Mileage: 58,000

I'm currently replacing new parts; radiator, intake manifold, and new carburetor. I'm almost done but ran into a problem trying to locate where this one vacuum line connects to.

On the stock carb there was a long metal vacuum line coming from the rear of the carb going down to the left rear of the engine (if facing the engine) and the line was not connected at the other end from the carb. I'm having difficulty with locating where this vacuum line reconnects to.

I have removed the stocked carb and replaced it with a new Edelbrock Performer carb with 600 CFM. Also, a new intake that matches the new carb. If possible, I'm trying to mimic the same set up as the stock carb. I'm not looking to burn tires but to remove that sluggish undertow drive I use to have. Better gas mileage is my goal actually but to feel the response when I hit the pedal. When I drove 50 mph it felt like 30. Any advice in this area on a V8 would be grand.

I've attached photos to give you an idea of how the old stock carb was set up. Let me know if they were not viewable.

If someone can tell me what size or speed transmission that would be helpful. I'm learning a lot of different models and make ups to this vehicle. It was hell finding the right size radiator.

Thanks for your help.

I suspect this line is supposed to go to the transmission's vacuum modulator. Don't know for sure though - back in 67 I was playing with a Plymouth Barracuda.

Regards:
Oldengineer