There's a mystique that comes from a pair of 4-barrel carburetors on top of a stout V8. On many occasions from the late s to late '60s, domestic manufacturers' top V8 engines were fitted with dual quads, and corporate-supported racers seemed to use them whenever they could—be it drag racing or road racing. Until Pro Stock's recent embrace of EFI, dual-quads were the standard bearer in the top door slammer class too, and they've been a mainstay on many a dedicated local drag car for decades.
While this knowledge may help explain the urge to use 2x4s on a street car, it isn't necessarily indicative as to the success of such endeavors. So what's the deal?
Are dual quads any good for the street in today's age? At least two factors are at play, and depending on your priorities, perhaps three. The first is drivability—in other words, can dual-quads be made to run well in a street application?
A second obvious factor is the performance of the setup, meaning that when properly dialed in, are dual-quads likely to perform better, worse, or on par with today's street 4-barrel applications? A third question involves cost; are 2x4s good bang for the buck? In an effort to dig through some of the ins and outs of running dual-quads on the street, we turned to Carl's Ford Parts and Blood Enterprises.
Carl's specializes in reissue Ford multi-carb induction systems, while Bloods is an experienced carb tuner and dyno shop in Auburn, Washington. Carl's helped us with parts and advice, while Blood Enterprises' Craig Blood brought his experience to bear as we dialed in a Holley-based dual-quad setup on Scott Wahl's '68 Mustang with a inch FE.
Follow along as we highlight five lessons we learned. If you end up buying an intake separately from your carbs, remember that carb spacing is critical. Likely scenarios here involve vintage Cobra-lettered small-block Ford intakes, versions of which were made in both Carter and Holley spacing. As well, Edelbrock dual-quad intakes both old and new typically have spacing that rule out Holleys.
Turning to another point of discussion, we believe it's a good call to buy your dual-quad carburetors new. Sure, some of you want original matching-numbers carbs for cars originally fitted with eight barrels, but that aside, consider a new purchase. For one, your target cfm combination could be difficult to find in used form. Two, getting multiple carbs to run well on a street engine takes some work, and the last thing you need is to be battling issues sourced from worn, gummed up, or mickey-moused swap-meet scores.
Both Edelbrock and Holley offer new dual-quad components or kits, while specialty vendors such as Carl's sell everything needed for a complete period-style setup.
Carl's can even modify a variety of Holleys specifically for 2x4 and 2x3 application, and not just for Fords. We've done several dual-quad tests in the last few years, and found going smaller than expected can result in a good balance of power and drivability on the street. As an example, we tested a inch small-block Ford with dual s from Carl's similar to Ford's over-the-counter small-block dual kitsand then tried dual s, which Carl's also configured for our application.
The s performed best in both drivability and total power, and handily beat a modern 4-barrel intake and carb it was tested against. More recent is the test we're highlighting in this story, which involved testing on a stout street-driven inch Ford FE.
First Craig Blood dialed-in the engine using a Quick Fuel double-pumper on a Blue Thunder dual-plane with medium-riser ports. Next, Blood fitted dual Holleys on a Blue Thunder dual-plane with medium-riser ports, and lastly tested dual s using the same intake. Production Ford FE 2x4 carbs ranged between and cfm each depending on application, but even on this big stroker motor, the dual s made a smidge more power and torque than the s, and were surprisingly just equal to the 4-barrel.
Our testing would seem to indicate dual s would be the clear choice on a smaller FE in the to inch range. We had our eyes opened when we went to bolt the Holleys to our test car's When we spoke with Tom Gipe about his experiences with a decade of owning and tuning a dual-quad ci Hemi engine, he had already written up a substantial description documenting his learning curve. His words and photos here are, except for clarity, largely unedited, and show first-hand the challenges he faced in bringing his Plymouth 'Cuda to tip-top running order.
To be honest, this began when the performance of my ci Dick Landy Industries Hemi engine had begun running dreadfully. This resulted in rough idling, surging, hesitation, and smelling up the garage with gasoline fumes that lasted for days. Since my Hemi 'Cuda has a Shaker hood scoop, a view of the engine and making carb adjustments is not easy without removing 20 minutes worth of hardware.
Coincident with my discontent with the operation of my 'Cuda, I read a series of articles on proper distributor and carburetor tune-ups to get optimal performance and helped to give me a path to getting this engine to run right. Reading this, along with forums on the internet, gave me the confidence to really do some extensive tuning and make my 'Cuda run its best.
What followed was about 18 months of repairs and tinkering starting in June that led to some very satisfying results. In the beginning of this Hemi's life, it was built by Dick Landy Industries back in Its major components were the stroker bottom end, a mechanical roller cam, dual Holley carbs, Stage V aluminum heads, and a Mopar Performance electronic distributor with Chrome MP box.
The intake manifold was the MP "marine" intake manifold because it has the spacing that allows the use of dual Holleys. When first built, dyno output was hp at 6, rpm and lb-ft at 4, rpm.
The engine is connected to stock Hemi exhaust manifolds that have been media extruded to smooth out the flow and are connected to a stock exhaust system to keep it as quiet as possible. Since the car now has a Tremec five-speed manual transmission with a Ram hydraulic clutch, the complications that come from connecting the carbs to automatic transmission linkage are a nonissue.
For observing what was happening, my first order of business was to remove the Shaker scoop. This initial inspection found that there were puddles of thick gasoline deposits residing in the pockets of the intake manifold below the carburetors. The car had recently been repainted and polishing compound dust found its way onto those sticky surfaces left behind by evaporated gasoline.
I assume that was to help race engines achieve better idle because of low manifold vacuum due to aggressive cam overlap. Unfortunately, it looked like gasoline sometimes emerged from the holes whenever positive pressure hit the venturis. That gasoline then ran down the side of the carbs leaving dust trails down to the intake manifold pockets where gooey gasoline residue formed. I concluded that these carbs were not suitable for street use. While Hemi engines came with AFBs stock, I like many aspects of the Holley design, especially how the accelerator pump has a sealed diaphragm versus the AFB's imperfectly sealed piston-type accelerator pump.
My first move was to replace the race carbs with Holley type cfm Classic Carburetors in aluminum model No.
I removed the electric choke assembly and choke butterfly of each carb. Removing the choke control unit on the side of the carb leaves a hole in the body of the carb that had to be plugged.
Also the linkage that connects the electric choke assembly to the butterfly left a hole in the air filter flange that also had to be plugged. To add some convenience to adjusting the vacuum secondary diaphragm springs, Holley quick-change tops were added.
I bought the ones that had the hose connections that allow better synchronization of the secondaries of the two carbs. Unfortunately, it was difficult to pull the hoses from the fitment end ridges, so they were left disconnected most of the time. The quick change top was convenient for testing springs, but they did not fit under the Shaker air cleaner base so the original diaphragm tops that these carbs came with were eventually reinstalled once the proper secondary springs were determined.Display Options.
Already know the part number you need? Click here to enter them directly into your cart. If you are an international customer who ships to a US address choose "United States delivery" and we will estimate your ship dates accordingly. If you are an international customer and would like to change the currency that prices are displayed in, you can do so here.
What is this? Loading Today Estimated International Date Loading Today. Fuel Linkage Kit 4-Barrel Throttle Linkage, HolleyHolleyKit. Throttle Linkage, Two 2-barrel, Stromberg, Kit. Loading Tomorrow Estimated International Date Low Price Guarantee. We're so confident in our low prices, we offer a Beat-a-Price Guarantee: We'll beat our competitors' advertised prices on any identical, in-stock product proof of advertised price required!
Carburetor Linkage Kits. Vertical Navigation Horizontal Navigation. Search Within Results. Narrow Your Results. Loading, Please Wait Sold as a kit. I am in the United States. International Customer Options. Delivery Options If you are an international customer who ships to a US address choose "United States delivery" and we will estimate your ship dates accordingly.
International delivery. United States delivery.My Account My Cart. Brackets And Linkage Just what you need to install your throttle cable the right way! Narrow Results.
Product Type. Items 1 - of Sort By Product Name. Page: 1. Part QFT. Part Accelerator Pump Arm Stud Kit. Part BR Brawler Linkage Kit super progressive Brawler Models. Part BQFT. Carburetor Throttle Lever Extension Chrysler. Carburetor Throttle Stud Compatible with countless Chrysler applications. Part DEM.
Brackets And Linkage
Flat Secondary Link Washer. Flat Secondary Link Washer Pack. Ford Kickdown Lever Kit. Trans Kickdown Lever Extension.
5 Tips For Dual-Quad Carburetion Success
Ford Trans. HP Microswitch Bracket. Idle Speed Screw Spring. Idle Speed Screw Spring Pack. Kickdown Cable Bracket for R-4 Transmissions. Kickdown Throttle Bracket for R-4 Transmissions. Linkage Kit super progressive.
Linkage Kit QFX super progressive. Mech Link DP. Mech Link DP Pack. Part G. Part MRG. Use as progressive set-up or straight to carburetors. Stud Kit GM Long.If you are an international customer who ships to a US address choose "United States delivery" and we will estimate your ship dates accordingly.
If you are an international customer and would like to change the currency that prices are displayed in, you can do so here. Image is a representation of this item. Actual item may vary. Change Currency.
Carburetor Linkage Kits
Loading Today Estimated International Date Check Fit. Brand: Summit Racing. Part Type: Carburetor Linkage Kits. UPC: Carburetor Quantity: Two. Carburetor Orientation: Inline. Progressive Opening: No. Quantity: Sold as a kit. I have a Customer Service question order, shipping, returns, etc. I would like to ask other customers a question about this Product.
I just mounted distances in larger wholes on throttel arm, and the pin with whole on downside approx in middle. I cut regulator-pin and kickdown-pin so they would fit my Chevy.
Register now to get rid of these ads! The H. I'm just looking for carb linkage idea's or info on a kit for my SBC. Gerry MoeDec 20, That's the other problem most kits are setup for sideways mounting of the carbs.
When you look closely all the parts are used on the sidemounts just different configuration. To fit your particular install just call them and give them your centers and they will correspond correct length arms. You see tha z that mounts the lower control arm it is actually backwards at least on the two that I have they mounted the other way, the z actually mounts the bracket your cables attach to. I think I will order the BDS linkage.
I hope the pedal is not too hard? Make it. It's not difficult. Use a compatible throttle pedal - Ford spoon, aftermarket spoon, 59 Ford stock pedal or make your own.CHARLIE PRICE VINTAGE SPEED 2x2 PROGRESSIVE LINKAGE ON STROMBERG 97 CARBS
That ain't hard either. I think some of the added force is coming from friction in some cable throttles. And tell me, how you gonna push the throttle shut if it sticks?Eldon, Missouri Selection and synchonization of dual carbs on either a four or six cylinder inline engine. Today, while a very small percentage will submit their vehicles to the race track, most are interested in dual carbs for either LOOKS ONLY, or looks with a modest increase in performance.
These two uses have vastly different requirements in carburetors. Typically, the manifold sold in the period would be drilled for two carbs the same size as the original a Chevrolet would have 2 S.
By using this arrangement, the user could order a second original carburetor from the dealer to go with original carb on the engine. Since the manifolds of today are basically copies of the manifolds of yesteryear, generally the street enthusiast will need to modify the manifold for smaller carburetors. Example: for a stock or modestly built Chevroletthe very best carburetors would be those designed for a Chevrolet If you plan to use on a trailered racecar, use the larger size.
Carburetors with a vacuum power system may be used, but the tuning MAY be more difficult. If you have a spring winding kit and feel comfortable hand winding small precision springs, you may ignore this paragraph. The next criteria is the one that gets the most arguments — the brand of carburetor to use. After almost 50 years of working on carburetors, we recommend Carters for most applications readily available, reasonably priced, and parts readily available.
For the high end user to whom cost is not an object, but perfection is the goal, we suggest either Strombergs are Zeniths. Other brands may be used, but there are no others that we recommend. In any event, one should choose a brand with which the user or the mechanic of the user is extremely familiar. Trying to use non-matched carburetors is simply asking for trouble. If you start with used cores, acquire good rebuilding kits we would suggest the ones we make ; and rebuild the carburetors to absolutely stock calibration.
Calibration adjustments, if necessary, may be made later. Once the carbs are rebuilt or new carbsone is ready for the installation and synchonization procedure, which is independant of brand, type, and size. Solid linkage will be required unless you have some funky home-made manifold that has both carbs feeding into a centrally located plenum. Progressive linkage is not an option. Synchonization A Make certain that you have two IDENTICAL carburetors check that the tag numbers are exactly the same, except for the production dateand that the carburetors being used are the approximate proper size for your application.