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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #1
On my new carb I need to run the dizzy vac line to a source.
on my old one there was only 1 port, now there are 2.
the one on the left is too large.
can I use the one above and to the right?
how can I tell?
thanks as always
 

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I think The left port is full manifold vacuum, your dizzy line goes there. The upper is timed vacuum, above the throttle blades, no vacuum at idle. Is there a port for the PCV valve? I haven't messed with a Q-Jet in years, so I may be wrong.
 

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RIP (12/27/60-7/18/15)
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767 Posts
Discussion Starter #3
the pcv valve dosnt go to the carb, it gets it vac off the intake man.
so are all the "full vacuum" ports off of the base plate?
 

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Premium Member
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4,703 Posts
TK, The vacuum line for the distributor goes to a vac port BELOW the throttle plates. So, if all your other vac lines are hooked up, you may use a reducer on the large (left) port and hook the dizzy hose there. You may also check the smaller port (right) , if it pulls vacuum at IDLE then you can use it. The object is to use vac that is below the throttle plates. :cheers E
 

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64-67 Expert
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8,561 Posts
Because it is.... Look at it. the bottom outlet is in the baseplate below the throttle plates. You want to run manifold vacuum to the dizzy if you can. That's the factory original method with '67's.
 

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5,741 Posts
I've heard recommendations both ways --- that distributor vacuum should be taken from a ported (above the plates) or a non-ported (below the plates) source. Actually, try them both and see which one your engine seems to "like" the best, and use it.

Bear
 
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