Slant 6 intake question

I am building a slant 6 from a 70 Dart that will go into a 68 valiant. As I am looking over the 2 intkaes, the one in the car now and the one that came with the motor I am building, I notice there is an outlet on the old intake that is not on the newer intake. The tubes or vaccum lines seem to go one to the brake booster and the other connects to the carb. Should I use the old intake or just try to remove the plug that is on the newer intake and attach the fitting and then the vaccum lines? Here are pictures of what I am referring to. The first one is the old motor intake with the lines attached. The second picture is the intake from the rebuild motor.

Remove the plug that is on the newer intake and attach the fitting and then the vaccum lines.

It sounds wrong that the 68's vacuum line runs to the carburetor (vacuum is already available there). It should run thru the firewall to the cabin, if you have the push-button climate control like my 69 Dart did. I see AC tubes (disconnected), so you should have push-buttons on the dash. If not using it, just cap off that vacuum port. If still confused, try posting in the Slant Six forum, or search at www.slantsix.org