Author Topic: Dual quad or not dual quad?  (Read 526 times)

Offline dlmwtvl

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Dual quad or not dual quad?
« on: December 04, 2016, 07:28:06 AM »
I am rebuilding a 66 401 and a st400, to install in my 65 Skylark.
Balance and blueprinting the engine to get the most horsepower, with drivability. This car will be not be a trailer queen.
My questions are:
Will a large Edelbrock carb give me the most power with reliability?
Should I go with the dual quad setup?
Should I go with Holley fuel injection?
Thank you,
David
ASE Master Tech
1966 Le Sabre 4Dr. HT 340 2bbl.
1968 Wildcat Conv. 430
1968 Riviera 430
1965 Skylark 2Dr. 300 2bbl.
1977 Le Sabre 2Dr. w/1970 stg.1 455

Offline WkillGS

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Re: Dual quad or not dual quad?
« Reply #1 on: December 04, 2016, 08:21:55 AM »
The Rochester Q-jet is likely the best performer but needs the '66-only intake manifold.
The '66 Q-jet carb has some design flaws, so a later carb with the 66-67 linkage swapped on is the preferred route. 'Rhett' has posted a few threads over at V8Buick.

Dual quads look better but don't perform as well as a single 4 bbl.

The AFB manifold can be modified for better performance, look up 'Doc's mod' for details. He likes the Holley carbs.
Some have used a 750 cfm AFB or Edelbrock with good results.
Walt K
Eastern Pa

66 GS Astro Blue/blue 425 auto
66 GS Silver Mist/black 401 4 spd
66 GS Flame Red/black 401 5 spd
66 GS Saddle Mist/black 401 L76 auto
66 Special Flame Red/black 300 5 spd
65 GS vert Verde Green/ Saddle buckets 401 4 spd
79 Turbo Regal

Offline wildcat65

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Re: Dual quad or not dual quad?
« Reply #2 on: December 05, 2016, 04:18:54 PM »
 
Walt- have you run a Q-jet on one of yours?

I JUST realized I have a 66 Q-Jet and Manifold.  I tried to install on my Riv, but with the different power and vacuum hook ups I
gave in to the path of least resistance on the Riviera.  But my GS has none of those problems, no P brake line, no trans vacuum line...
I think that the Q-jet may have to be tested soon.  Carmen built it for me, ready for action.

OP- currently have an edelbrock that was dyno'd on the engine.  I'd say no to the Edelbrock unless you are willing to do some serious testing or dyno the engine with the carb.  My engine has a cam and needed a LOT of jetting help on the edelbrock. 

Holley set up sounds interesting but may need an adapter to bolt on the manifold.

Cheers

Ted Nagel         65 Skylark GS 4-speed + Wildcats + GS's

Offline WkillGS

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Re: Dual quad or not dual quad?
« Reply #3 on: December 05, 2016, 10:36:14 PM »
Yes, I had a '66 Q-jet carb on my blue '66 at times, but the 2x4 is usually on there.
My 2x4 setup uses a pair of 500 cfm AFB Comp series carbs. Very driveable with great throttle response. What surprised me A LOT was how much more top-end power it had with the Q-jet!

Also have a Q-jet on my red '66 with the 5 speed, and of course, a Q-jet on my gold '66 which is original to the car. That one is still in 'project car' status.
Walt K
Eastern Pa

66 GS Astro Blue/blue 425 auto
66 GS Silver Mist/black 401 4 spd
66 GS Flame Red/black 401 5 spd
66 GS Saddle Mist/black 401 L76 auto
66 Special Flame Red/black 300 5 spd
65 GS vert Verde Green/ Saddle buckets 401 4 spd
79 Turbo Regal