Topic: Air cleaner base - vacuum tube diagram (400)

[WyoTA]

Hey guys, probably a very basic request here but does anybody have a diagram, or photos they could share, illustrating a correct vacuum tube setup for a pontiac 400 air cleaner base with Rochester 4bbl carb? I'm interested in even where the line coming off the snorkel A/C should be properly installed. This is for a '79 if that matters here.   

Thanks!

[Wallington]

I don't have a 400 but I'll step in until someone else bothers. This area is basically the same with all snorkel valve units. The vacuum line goes under the base to a twin port sensor switch, it's seen inside the base and says AC on it, looks like little contacts inside it. From there it runs around the back of the base to a vacuum port on the carb. The later years, and I'm guessing 400 in '79 as well, went first to a TVS switch on the side of the aircleaner. These can be 3-port or 2, I think the 400 used the blue 2-port. The arrangement from there is usually one direct and one to secondary choke pull-off valve but not sure. That's probably more confusing than before now.

Or check some of these pics:

http://transamcountry.com/community/index.php?topic=43554.0