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Drivetrain => The Dual Quad => Topic started by: nailr65 on January 10, 2010, 08:36:59 AM

Title: Looking for Carter for a 65 dual quad set up
Post by: nailr65 on January 10, 2010, 08:36:59 AM
Does anyone have any idea what the prefered size carters I should use on a dual quad set up for a 1965 401?  Trying to keep that stock look.  I have a stock intake and the stock super wildcat air cleaner.  Just need the carbs and the linkage.  The linkage is available here on the forum. 
 Thanks Dave
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: WkillGS on January 10, 2010, 12:00:18 PM
Dave, a pair of 600's would be good for a street car. If the engine is modified, there are a couple of guys that run a 6oo in the front for normal driving, and a 750 in the rear for extra power. For a cruiser, even a pair of 500's will work nice. Stock size was 625 cgm.

But it's not that easy. The aftermarket carbs have a larger 5-1/8" top that won't fit the stock air cleaner. You have to put a spacer there to adapt it. I used a 1" high ring can from a coffee can to adapt it.

A more economical  option is to find a pair of stock 65 Buick 1x4 carbs and use those. A #3921 is a common 65 Buick carb.
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: nailr65 on January 12, 2010, 02:50:20 PM
Walt, thank you for the detailed reply.  I have pulling my hair out trying to get some real info on what would be the best way to do the conversion.  Thanks again.

Regards Dave
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: kcombs on January 13, 2010, 09:30:31 PM
There's one carb on Ebay now.
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: dsags on January 14, 2010, 08:02:32 AM
Here's the link http://cgi.ebay.com/ebaymotors/Buick-nailhead-rat-rod-2x4-rear-carb-425-carter-3645sb_W0QQitemZ150404966360QQcmdZViewItemQQptZMotors_Car_Truck_Parts_Accessories?hash=item2304d5a7d8
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: 65GS on January 14, 2010, 07:14:25 PM
3645 is for the front carb not the rear carb on a 2-4 setup. the rear carb is #3924. easy way to tell is rear has a large air bleed bolt bolt between the idle adjustment screws.
hope this helps. :occasion14:

Al
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: wildcat65 on January 20, 2010, 02:13:35 PM
Rear carb.  This ones for a 4=speed Wildcat...I'd bet almost all dual quad Skylark GS
cars have carbs from a Riviera...automatic.   

(http://i51.photobucket.com/albums/f376/Wildcat65/DSC00085.jpg)


Title: Re: Looking for Carter for a 65 dual quad set up
Post by: Loren At 65GS on January 20, 2010, 06:47:27 PM
Mine is powered with a complete "LX" engine from a Wildcat. All original carbs, aircleaner and alluminum valve covers.
Got lucky with that one. All I was looking for at the time were the valve covers. They were attached to an engine the guy wanted to get rid of.

Loren
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: nailr65 on January 24, 2010, 12:28:52 PM
Gentlemen thank you for all the info.  it has been a great help.  Now I just have to get lucky and aquire the carbs.  I'm on ebay every day.  They pop up now and then but usually rough and going for big bucks.  Just have to be dilligent.

P.S.  Hey Ted Sweet Carb do you want to sell it  :overthetop:
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: Chris on January 24, 2010, 06:52:07 PM
Still under $200 with a day to go.. better hurry up!    :blob7:

http://cgi.ebay.com/ebaymotors/CARBS-BUICK-DUAL-QUAD-2X4-RIVIERA-64-65-66-NAILHEAD-GS_W0QQcmdZViewItemQQhashZitem439ccbeb03QQitemZ290393418499QQptZRaceQ5fCarQ5fParts
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 05, 2010, 11:07:50 AM
Do you guys ever see the correct originals around at swap meets or other events?  I can't find them anywhere on ebay.  And wanting correct carbs for a manual transmission application appears to be virtually impossible.

What are the differences between manual and automatic carb designs?  I believe one uses ported vacuum to the spark advance module and the other uses direct vacuum.  Is this correct?  Any good reason to not use an auto carb on a manual?  Especially for the rear carb.....

Thanks,

Chuck
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: Mark Ascher on February 05, 2010, 02:23:23 PM
Calling Brian...

Mark
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: Brian on February 05, 2010, 03:04:14 PM
Yes, that is the difference--ported vacuum on the manual trans carbs and manifold vacuum on the auto trans cars.  Seems like there is one other minor difference too, but I can't remember off the top of my head.  The auto carbs will work fine on a manual trans car. 
  In fact, if you have a big camshaft in the engine, you will have to hook the vacuum advance to manifold vacuum to get it to run right, otherwise it will stumble and fall on its face when you let the clutch out and the engine rpm drops a little, causing the vacuum advance to retract and it is downhill from there.   On an engine with a stock camshaft, the ported vacuum on the correct man. trans carb works fine.
   I think the reason they did the man. trans carbs different like that was to meet some basic emissions requirements that started in 64.  More retarded timing at idle (as a result of ported vacuum), helps reduce NOx and CO.  It is more of a problem on manual trans cars because there is zero load on the engine when idling in neutral.  Auto cars are always turning the torque converter and pump in the transmission.
   And if you ever find a correct rear 2-4's, manual trans carb, let me know and I will buy it from you for some good $$   I have never even seen one personally. 
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 05, 2010, 03:21:17 PM
Thanks Brian.  Sounds like I need to be happy with a 3921 or a 3925 if I can find one.......

Cheers!

Chuck
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 05, 2010, 03:33:28 PM
One more question after rereading Brian's post.  Which carb would be preferable for the rear on the 2X4 setup?  A '65 3921S or a '63 3578S?  Less emission impact on the 63 model?  Does anyone know the difference between them? 

Chuck
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 22, 2010, 04:51:48 PM
I just made a purchase and hope it will work.  I bought the correct carbs for a 1964 automatic dual quad setup.  Front carb is a 3645 and the rear is a 3646.  Any problem using this on the '65?  I haven't studied the manual trans linkage so I don't know what differences there might be.  I also notice that the rear carb has a vacuum port plumbed below the throttle blades.  See pictures below.  I know the front carb is the same number for '65 and hope the 3646 will work well in the rear.  Any comments?

I'll have a couple of incorrect carbs to sell now......

Some linkage and mounting parts came with the carbs and the aluminum bracket in the pictures I don't recognize.  Anybody know what this is for??  Be sure to look beyond Danica in the next to last picture so you can see the part number  :-)

Thanks,

Chuck
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 22, 2010, 06:23:39 PM
One last question......where do you get the heat riser tube for the automatic choke?  Are there sources available or do you fab your own?


Thanks,

Chuck
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: 65GS on February 22, 2010, 06:25:21 PM
If memory is correct, the vaccume port is for the vac. modulator on the Automatic trans. :occasion14:
Al
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: WkillGS on February 22, 2010, 08:32:07 PM
If memory is correct, the vaccume port is for the vac. modulator on the Automatic trans. :occasion14:
Al

Fab your own from steel brake line tubing. The brass nut at the carb is a std plumbing supply item.
Title: Re: Looking for Carter for a 65 dual quad set up
Post by: cwmcobra on February 22, 2010, 09:52:32 PM
Thanks guys!

Chuck