Turbo Q-jet vacuum question

[chuck79]

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I've got a Q-jet off a '79 Turbo Regal for my 4.1. I have to hook up a vacuum like to the port right under the fuel inlet. Does anyone know if it's a ported or manifold vacuum?

[crawfw]

If its under the throttle butterflies, it should be manifold vacuum. If there is vacuum present at idle, it is manifold vacuum.

[chuck79]

The guy I bought the carb from stated that the port in question had to be hooked up to a external vacuum source. The vacuum does not come internally through the carb. Otherwise it won't run right. Something to do with a power valve that requires vacuum. It's been a while.

[Monza Harry]

Chuck that sounds right, but I would go to a Turbo Buick site and post there. I know that draw through carbs have power valve issues, do to constant vacuum from the blower/turbo. That is one of the many reasons for failed home turbo swaps. The gang on the blown/turbo car forums have had to deal with this and know much more than I on the subject, as soon as I win the lottery I will commence a learnin' 'cause I WANT a blower! Harry

[chuck79]

Thanks Harry.

[chuck79]

http://www.78ta.com/HTAF/index.php?topic=9215.0
The port in question is for the pevr valve, clears up a lot of info for me. Seems I put a pevr valve into the manifold, run the lines to connect it and I'm golden. Any other thoughts?

[chuck79]

I've put the carb for sale in the for sale section if anyone is interested. It looks as if the pevr valve is an unobtanium 1 yr. only part unless someone else knows different. This is a good carb. I would hate for it to be wasted. I've purchased a '79 Corvette q-jet off ebay. Change the jets and adjust the secondary for less airflow should do it after a good rebuild.