Ok I have searched everywhere and cannot find anything about the vertical tube? vent? whatever it is, that goes just in front of the heat riser. The repo manifolds have the casting but are not machined. I have looked in the FSM and cannot find a reference on it.
What is it's purpose and who has the parts.

Thanks

The purpose is that it sends hot exhaust gas to the intake manifold to help with the choke operation. As the engine and intake warms up the flapper will open and the choke will have opened.

IIRC In 71 it is not used as it has a manual choke.

The larger tubes above the heat riser direct exhaust gasses to the intake to heat the plenum, the smaller nipple in front of them is for the tube (white insulated tube in pic below) that heats the choke; it is hot air only, no exhaust gasses.

Yes John that is exactly what I was asking. So what is the natural metal line running along the white sleeved line? Is that a double clip holding the natural line and the white sleeved line? And finally does anybody have these parts. The tube that goes through the manifold, the line with the white sleeve and the clip?

Thank you so much for the help. I have been searching for this for weeks.

The natural metal tube is hooked to the air cleaner and supplies a clean air source, the vacuum inside the choke module pulls the clean air down into the exhaust manifold where it is heated by the heat exchanger inside the manifold and is then drawn into the choke module through the insulated tube to heat the spring.

Most of the choke parts are available on e-bay.

http://www.ebay.com/sch/i.html?_from=R40...amp;_sacat=6000

Thank you for your help John!