I am mocking up a super six with a 1974 BBD for my 1975 slant six. I am making sure that I have the vacuum lines set up correctly.

When viewing the carburetor from the front where the fuel line enters the float bowl there are two vacuum ports:

Canister purge between the idle mixture screws
The air pump diverter valve (which I have capped)

http://i748.photobucket.com/albums/xx12 ... C06699.jpg

When viewing the carburetor from the side with the choke diaphragm there are two vacuum ports:

The float bowl to canister
The distributor

http://i748.photobucket.com/albums/xx12 ... C06700.jpg

When viewing the carburetor from the back side looking at the curb & fast idle adjusting screws there are are three vacuum ports:

The PCV
Heated Air
The choke diaphragm and egr t-ed together

http://i748.photobucket.com/albums/xx12 ... C06702.jpg

A few more pictures:

http://i748.photobucket.com/albums/xx12 ... C06703.jpg
http://i748.photobucket.com/albums/xx12 ... C06704.jpg

Do these vacuum ports sound correct?

I also have a cast iron intake manifold and an aluminum manifold are there any benefits or disadvantages to using one over the other?

Thanks,

Chris

I think you've got the ports correct -- Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download, and there's a BBD book in the collection.

Aluminum's nicer if it's unwarped and uncracked. If it's the yellow one in the pics, it's one of the EB-welded intakes (prominently visible weld bead all around the upper perimeter of the manifold) so it will want very careful inspection for cracks in the floor.

_________________
一期一会
Too many people who were born on third base actually believe they've hit a triple.

Thanks Dan, I was most concerned with the choke diaphragm and the egr being fed by the same vacuum port but I have found some information that seems to support the idea that they indeed did share the same port on some applications.

I have read about the problems you mentioned with the aluminum manifolds, I am going to media blast the manifold to remove the yellow paint and after washing the manifold I will check for cracks inside and outside of the manifold.

http://i748.photobucket.com/albums/xx12 ... C06730.jpg

Thanks for the help,

Chris