Thread: Qjet vacuum ports question

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I am installing a Qjet on my small block Chevy and since I have never worked on a Qjet before, I need help with a few items:


Pictures are below. I'm not exactly sure what vacuum port does what. For example, is above the throttle plates ported vacuum? I have to hook up:

PCV (Full manifold vacuum) - hooked to number 5
distributor (ported vaccum)
TH350 trans (??vacuum) - what type of vacuum do I want here?

While I'm at it, how do I adjust my Lokar kickdown cable? Lokar instruction say to make it tight at full throttle. Just want to be sure.

Are you suggesting that the choke take-off is mis-located? I had a local guy rebuild the carb and this is the way it was returned to me.


I'm confused about Dist vacuum. You say that I should put the dist vacuum to the place where the choke pulloff is now, but isn't the current choke puloff location, and #1, both ported? You also mention that most Chevy's run full advance at idle (did I understand that right?). How is that effective if the vacuum goes down (and timing goes down) as rpm's go up?




So for my setup (355, alum heads, dual plan intake, rams horns, mild cam), what would HIE vacuum setup would you recommend?

Thanks Denny, I did not mean to second guess what you were saying, I'm just trying to learn it for myself. I super appreciate the help and walking me through it.

OK, so the choke pulloff is incorrect, I will fix that.

I do have light advance weights on my HEI, yes.

Here is how I understand vacuum advance, correct me where I am wrong: As rpm's go up, ported vacuum goes up, manifold vacuum goes down. When the vacuum advance unit on an HEI gets vacuum pulled, the timing is advanced. When the unit sees no vacuum, there is no additional vacuum advance. Therefore (I thought), that as the rpm's go up, you need and want additional timing (above and beyond the weights).

I am perfectly willing to try using manifold for vac advance as long as I understand why. In fact the guy who rebuilt the carb is coming over this weekend to help me dial it in, and he suggested Manifold vac too.

So if I were to switch over to manifold vac for distributor, should I keep the light weights? (my prime powerband is 2000-4000)

Edit: I found these pics on Ebay to see some more vac examples of pull -off (as you said).

I got it, thanks Denny.

I also read this post which gives me some more insight (see below). I will be trying manifold vac as a starting point.

http://www.clubhotrod.com/t9877.html

There's an older thread titled "Got Time?" that's has some good info too.

edit: Found it. http://www.clubhotrod.com/forums/showthread.php?t=13909