"Original" Quad Set Up

Discussion in ''Da Nailhead' started by rlafash, Jan 18, 2010.

  1. rlafash

    rlafash Well-Known Member

    Please take a look at the attached pictures of the dual quad set up I purchased for installation on my 66 Skylark GS. I am concerned with the "kick down" switch and bracket. The switch and bracket are different from all other original dual quad set ups I've seen and from the switch and bracket shown in the Buick Parts Manual. It appears as though the switch will operate since the roller on the linkage of the primary carb does depress the plunger of the switch. However, the original dual quad set up's I've seen use the same "kick down" switch as the one on my single four barrel set up which operates by extending the switch shaft forward, exactly opposite from the one I purchased. Is this an "original" Buick product? If so, on what car(s) and in what year(s) was it used?
    Also, the seller powder coated the intake, however, he used Buick Engine Red from the 1930's. I plan to repaint the intake using the correct 1966 Buick Engine Red Hi-Temp paint. Are there any negatives to painting over the powder coat? Thanks for your help!

    Attached Files:

  2. nailheadnut

    nailheadnut Riviera addict

    This looks exactly like the illustration for the OE 2x4 set up in my '64 chassis manual. The '64 TH400 didn't have the switch pitch transmission so it didn't need the extra wires that were required in '66 to operate the s/p when the throttle linkage was at idle. What is the intake manifold casting number and the carb numbers? If you're not happy with it, I would be. It would look perfectly at home in my '64 Riv's engine bay. ;-)

    Last edited: Jan 18, 2010
  3. doc

    doc Well-Known Member

    Ed, is right on.... that switch looks just like the sw. that is on my 64 riv.... single 4 set up....
  4. rlafash

    rlafash Well-Known Member

    I will confirm the intake and carb numbers later today. My 66 Skylark GS has been re-fitted with a THM400. Will this "kick down" switch work properly with this transmission? The dual quad set up is complete including the air cleaner and proper "acorn nut". If it will work properly on my car, I would not be interested in selling it. I would be inclined to obtain the correct primary carb linkage, kick down switch and bracket. Thanks for your help.
  5. nailheadnut

    nailheadnut Riviera addict

    While you're looking for casting numbers and carb numbers, you might as well find the transmission number. It's on a plate on the passenger side of the transmission. It will tell yo the year. 64 doesn't have the s/p feature, but 65 and 66 do. The other (simpler way) is to look at the electrical sending unit on the driver's side of the trans. One terminal - 1964- and the kickdown set up you have is fine. Two terminals - 65 or 66 - and you'll need to find the correct kickdown for the s/p. The kickdowns you're looking for are (IMHO) about 100 times as rare as the dual quad setups.

    The '66 Skylard didn't come with either the 2X4 set up or the ST400 trans. There are numerous aftermarket units available to handle the s/p on launch. You can wire your brake light switch to handle the s/p at idle - if you want it. The factory did away with it in '68.

  6. rlafash

    rlafash Well-Known Member

    Ed, thanks for your reply's and information. The car itself is in stotage, however, I'm virtually positive that the transmission is 65-66 as I believe it has a sending unit incoroprating two (2) terminals. I will not have access to my records which have the intake and carb numbers until sometime tomorrow. Seems to me I'll need the proper throttle linkage for the primary carb, the correct kick down switch (same as the one on the single four barrel), and most important the correct bracket for that switch. If you'd like, I'll send a few pictures of the air cleaner next time.
  7. nailheadnut

    nailheadnut Riviera addict

    Chances are you can cut and rethread the linkage you presently have to make your arm for the primary carb - It's probably a snap fitting at the carb, and there's a threaded bracket at the pedal linkage.

    Do a BUNCH of reading on the ST400 w/ switch pitch to determine exactly when you'll want your transmission to slip into high stall. Most guys who are using the high stall as a higher ratio first gear have done away with the OE set up by now. The instant you take your foot off the brake/apply any throttle pressure (depends on year) the s/p goes to low stall. IF you want to use high stall to help you launch off the line quicker, you won't want the OE set up anyway.

    If I were you, I'd modify the linkage I have for the primary carb, use the kickdown you have to activate the kickdown, and if you really think you need it high stall at idle, wire the kickdown to your brakelight switch.

    Sorry, here's some offsetting news based on your last post. If you want to use the correct switch and bracket from a '66, you're going to also have to add to your list of things to find - the correct primary carb - the carb you have won't work. :ball:

    The carb throttle linkage you have pushes on the switch; the carb throttle linkage you'll need for a '66 OE set up pulls an arm on that switch. IF you can find that carb, you'll be looking at beaucoup bucks. It's hard to find someone who's willing to breakup a set of carbs. The 2x4 set up in '66 wasn't available from the factory until March of 66 (MZ code engines.) However, the set up could be ordered through the parts dept. and dealer installed. Electras and Wildcats had a single AFB carb; Rivieras came with a Qjet. The s/p linkage was the same and the linkage on both carbs works the same. I've attached a picture of a '66 Qjet, the rod, and the switch. You might be able to find an OE AFB for a '66 and use it as your primary carb by checking the jetting and metering rods. That shouldn't be too expensive.
    '66 s/p for high stall when the car was at idle was a micro-switch on the accelerator pedal assembly on the firewall side.

    Remember, all GM TH400 transmission have electric kickdowns. There has to be a ton of OE stuff to look at to make this work.

    As I said earlier, read up and see exactly how and when you want the switch pitch to activate before you start chasing parts.

    Something else to think about. If you have the converter for the original ST300, you can use it with the ST400. The high stall for the converter will be even higher. Use an auxillary trans cooler if you do this. Makes for a very quick car off the line.


    Attached Files:

    Last edited: Jan 19, 2010
  8. rlafash

    rlafash Well-Known Member

    The casting number on the intake is B1370316B; the front carb is 3645S; the rear carb is 3645SA. I plan to contact the seller in order to see if he might have the correct carbs for use on my 66 Skylark without the modifications that appear necessary to adapt the set up I now have. I believe that 4050S(front) and 4051S(rear) would be what was used in 1966. Are there others that would have the correct linkage on the carb for use as the rear carb? Thanks!
  9. Brian

    Brian Displaced VA Hillbilly

    Carman Faso sells repo 65-66 2-4's kickdown brackets. I have a throttle arm off of a single 4-bbl. AFB that I modified to have the connection for the linkage to the front carb. It can be changed by filing off the edges where the end of the shaft is bradded around the arm, slide the old arm off, slide this one on, and re-brad the end of the shaft with a ball peen hammer. Let me know if you are interested in it.
  10. rwg65

    rwg65 Well-Known Member

    Dick, the front carb is right, you need an 3925sa for the back. That's what is on mine.
  11. rlafash

    rlafash Well-Known Member

    Thanks for the info on the front carb. I'm exploring several alternatives including the purchase of a complete numbers matching set up and selling my intake, carbs and air cleaner. The original seller will trade me for the correct 1964 intake so that my set up would be numbers matching for 1964. The responses I've received have been very encouraging.
  12. A67Skylark

    A67Skylark New Member

    One on ebay 3925sa, not mine either..
  13. rlafash

    rlafash Well-Known Member

    Thanks so much for the information on the #3925SA carb on ebay. This shows the attitude of helpfulness of the members of this board.
    The good news is that I have been in contact with the seller of the set-up I purchased. He is in the process of restoring and re-building a #3924SA and #3925S for me. Can anyone one explain the difference(s) between the #3924SA and the #3925SA and the #3924S and the #3925S? Will "mixing" the #3924SA with a #3925S be a problem?
    If all goes well, I may have the original set up for sale, that would include the #1357106 intake, powder coated the correct Buick green for 1964, the #3645S and #3645SA, the correct kick down switch and bracket for the 1964 Rivera, all numbers matching. It would not include the air cleaner assembly although one might be available. Let me know if anyone is interested.
  14. John Codman

    John Codman Platinum Level Contributor

    Hi Ed (nailhead nut), Are you sure about the 1966 Quadrajet being available only on the Riviera? My 425 (red, so it's a '66) supposedly came out of an Electra. I never saw the car, but the engine was sitting under a beat-up old yellow hood that looked like an Electra hood to me. The engine was equipped with a Q-jet that appeared to be original.The person from whom I purchased the engine told me that he had personally removed the engine from a '66 Electra convertible. There was no switch for the transmission on the manifold, but it could have been removed before I purchased the engine. The Q-jet has a provision for a piece of linkage other then the throttle cable.
    I thought that someone in another post here said that Riviera engines were painted silver. You have aroused my curiosity.
  15. nailheadnut

    nailheadnut Riviera addict


    That's what my information tells me. Look at the VIN on the valley pan surface - right behind the water crossover, driver's side. The second and third numbers tell the model. 64-Wildcat, 66-Wildcat Custom, 82-Electra, 84-Electra Custom, 94-Riviera. I got this info from my '66 Chassis manual.

    I have no resources that tell me if the 425 was available in the Wildcat or Electra series. The only thing that gives any hint of any possiblities is that the Rochester 4MC (quadrajet) is shown only for 425 applications. The Carter AFB's are shown for 300/340 and 401 applications. The only thing I'm 99%sure of is that only the Riviera engine was red. (The 300/340's were red but they're not nailheads.)

    The engine code should be on the opposite side MT for a 401, MW for a 425. Who knows, it might be one of the rare Q-jet equipped 401's that came out mid year in the '66 Skylark Gran Sport line with a four speed. There wouldn't be a switch on these motors. Does the engine have a flex plate, flywheel, or neither?

    There's nothing in the chassis manual about what engines were available for which models. There are all sorts of possibilities here; hopefully the VIN will give you a clue.

    After so many years, and because the engine is missing the s/p-kickdown switch, it's really hard to tell how may have done what to the engine over the years.

    I would appreciate it if you'd let me know what you find.

  16. John Codman

    John Codman Platinum Level Contributor

    Hi Ed,
    Will Do. I am hoping to be at the place where my 425 (I'm sure of that) powered Chevy pickup is located (35 miles away from La Casa Grande) tomorrow. I will check the numbers and be back to you sometime late tomorrow - assumming that everything goes according to plan.
  17. nailheadnut

    nailheadnut Riviera addict

    John, I see that you list a nailhead powered C-10 as one of your rides. What's that like? What would you think of a nailhead powered S-10? Would it be worth pursuing?

  18. Wildcat GS

    Wildcat GS Wildcat GS

    The 425 was available in the Wildcat and Electra in `66. They are painted red and equipped with the Quadrajet.
    Tom Mooney
  19. Schurkey

    Schurkey Silver Level contributor

    If this were me, I'd keep the carbs, linkage, and kickdown switch AS IS, and just install a Bruce Roe ELECTRONIC switch-pitch controller hidden under the dash.

    The electronic controller is about a hundred times more sophisticated than the crappy on/off/on switch GM used; and uses the switch-pitch to it's fullest potential.

    This does assume that the trans HAS the variable-pitch torque converter that would have been standard equipment in '65, '66, and '67.

    Contact Bruce at bcroe@juno.com and tell him Schurkey sent you.
  20. John Codman

    John Codman Platinum Level Contributor

    Hi Ed, I am now more confused then ever. My engine is a 425 - I knew that long ago as I had it rebuilt. The code on the right side is MW. The number on the left side is 849858 which does not match anything that I know about. What gives?

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