Dizzy/vac can???
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Ported is emissions crap.
Manifold (full vac) is performance non-crap.
Pick your port. Usually off of the front of fuel / air blender.
Manifold (full vac) is performance non-crap.
Pick your port. Usually off of the front of fuel / air blender.
Last edited by HeadsU.P.; Jun 8, 2020 at 08:41 AM.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
Sorry. Have not owned a QJ since the 70's. Not my thing. I prefer the Holley blenders.
Once you find your correct port, cap the other. That little trick should gain you over 2.74 H.P.
Once you find your correct port, cap the other. That little trick should gain you over 2.74 H.P.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
The canister itself doesn't care if you have a QJ, Holley, Q. Fuel or Eddy.
The canister wants a specific vacuum range to operate in depending on the amount of vacuum your engine is pulling at different throttle positions.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
In almost any case, you want vacuum advance connected to manifold vacuum.
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Just something to think about---
Many 'performance' folks have great disdain for vacuum advance. Why? I'm not sure. When at WOT, the vacuum advance [for all practical purposes] has no effect on ignition timing. Manifold vacuum is nearly ZERO at WOT, so no change to ignition timing because of the vacuum advance. The purpose of vacuum advance is to obtain a smoother idle, lower engine temps at idle, and better economy at idle and low speed cruising. That should be an asset to anyone.
_______________
Just something to think about---
Many 'performance' folks have great disdain for vacuum advance. Why? I'm not sure. When at WOT, the vacuum advance [for all practical purposes] has no effect on ignition timing. Manifold vacuum is nearly ZERO at WOT, so no change to ignition timing because of the vacuum advance. The purpose of vacuum advance is to obtain a smoother idle, lower engine temps at idle, and better economy at idle and low speed cruising. That should be an asset to anyone.
