Choosing the right Stromberg 6×2 linkage

So you’ve got yourself a cool 6×2 intake, either a new cast manifold like the Edelbrock X1 ram or the Offenhauser Pacemaker 3924 (low-line), or a U-fab or log-type intake, and you’ve stepped up for six 97s. What you need now is a quality, sturdy linkage that won’t flex when you stick your foot in it, and won’t swamp your beautiful carburetors with huge brackets or weird curved linkage rods going in all directions (yes, we’ve seen them too).

Stromberg has 6×2 progressive and direct (non-progressive) linkages to fit pretty much everything out there. This means ready-to-fit kits for those popular intakes that are available brand new. And ‘Trim-to-Fit’ kits for everything else. The direct linkages come complete in one box. And the progressive linkages are modular, so you can always get the right parts for your intake. Here’s how they work…

Choosing the right 6×2 Direct Linkage kit. Let’s get the easy ones out of the way first. Right now, we offer three 6×2 Direct Linkage kits.

Got the Edelbrock X1 ram 6×2 intake? You need our 9261-D 6×2 Direct Linkage Kit. It spaces the carburetors 4-7/8th inch in front of each other and 9-1/8th inch apart across the intake, and there is no offset between the two banks of carbs. This linkage is ready to go, comes almost completely assembled with the Back-bar levers pinned to the shaft and even though it bolts straight on, it still comes with full instructions, of course.

Got the Offenhauser Pacesetter 3924 6×2 intake? You need our 9262-D 6×2 Direct Linkage Kit. This is a low-line intake compared with the X1 so it can give you a little more clearance for low hood applications. It spaces the carburetors 4-3/4 inch in front of each other and 6-1/2 inch apart across the intake, with the carbs on the US driver’s side 3/4 inch offset in front of the other bank. As before, this linkage is ready to go.

Got something else? You need our 9260-D 6×2 Trim-to-Fit Direct Linkage Kit. It will work with intakes that space the carburetors up to 5-1/2 inch in front of each other, up to 9-1/8th inch apart across the intake and up to 1 inch of offset between the two banks of carbs. Believe us, that’s going to cover pretty much every production engine around. How difficult is the trimming? You’ll be drilling and maybe shortening one bracket and adjusting the lengths of the rods. And everything is explained in the Installation Guide included. Download a copy right here in our Tech Center if you’d like to see it first.

Choosing the right 6×2 Progressive kits.

A 6×2 progressive linkage is really just two 3×2 kits plus the Back-bar which joins it all together. With so many different variables between intakes, that’s also how we offer them. Here’s how to order the right kits for your intake:

1. Measure the carb to carb spacing – from one throttle shaft to the carb in front. Then order two kits – one for each bank – of the correct Stromberg 3×2 progressive linkage to suit your carburetor intake spacing. There’s a list of which linkage fits which spacing below. If your spacing is not covered, buy the next size up and trim down the threaded rod between the secondary (outer) carburetors. Trim the right hand threaded end and add more 3/16-32 UNF thread if required.

For this spacing….use this kit

4-9/16inch………..9243PRO

4-3/4inch………….9253PRO (fits Offenhauser Pacesetter 3924)

4-7/8inch………….9251PRO (fits Edelbrock X1 ram)

5-3/16inch………..9245PRO

5-1/2inch………….9246PRO

2. Now add the 6×2 Progressive Back-bar Kit to link both carburetor banks together. 6×2 intakes can differ in the space and offset between banks.

For this intake…………….use this kit

Edelbrock X1 ram………..9261-BB

Offenhauser Pacesetter 3924…….9262-BB

Anything else……………..9260-BB (Trim-to-Fit)

It might also pay to compare the spacing, width and offset of the Edelbrock and Offenhauser intakes (see above in Direct Linkages) to see if they are nearer to your requirements.

Your link to the pedal. Stromberg recommends a mechanical pedal link for all multi-carb systems. Ideally, your 6×2 Back-bar can be connected to the pedal via one of the long levers that work the two banks of carburetors (they have three adjustment/connecting holes at the top). However, if these do not line up with your pedal link, you can add a third long lever to the Back-bar shaft with Stromberg kit 9096K (Long linkage arm/swivel) positioned to align with your throttle pedal ‘pull’ point. Complete with swivel, clamping screw and 3/32” roll pin, the 9096K lever can also be drilled and pinned to the Back-bar to ensure positive location.

You can download this Tech article at the Stromberg Tech Center (click the link). As with all our Tech articles, we welcome customer feedback and other input. Email us (tech@stromberg-97.com )with your thoughts and if it adds to the debate, we’ll it in.

8 thoughts on “Choosing the right Stromberg 6×2 linkage

  1. i have a WEIAND DRAGSTAR CV6 manifold with 6 ford ( holley ? ) carbs its not together yet but i am thinking ( guessing ) your 9262-d is the kit for this do you have any information/experience to confirm if this is correct or am i going to have to use your trim to fit kit
    thanks
    mick

    • Hi Mick. I am sorry, but our back-bar kits do not fit the later Ford/Holley carbs as they have the idle mixture screws on the back so you cannot mount the back-bar brackets on that rear stud.

    • Hi James, From the customer feedback we have had, the Nailhead responds to a lot of fuel and air. For a street driven 6×2, I would recommend a progressive linkage with two BIG97 Primaries in the centre and four regular 97s in the outside positions. This gives you a good rpm range on just the primaries before you bring in the secondaries. So you have the best of both worlds. Good response at the bottom end with a decent rev range for cruising on just the primaries, and then up to 1150cfm is and when you need it at the top end.

  2. I was told you can not use progressive linkage on a off 3924 manifold on a small block chevy as you will lean out the front and rear cylinders is this true. ?

    • Hi Kevin, I have never run one personally so I would always bow to someone with experience. I remember one flathead expert telling me the same about any 3×2 intake! While this 6×2 intake certainly has passages to connect the centre carbs to the outer cylinders, those outers are also right over the intake ports so I can see why people think this. One argument is that all of those ports have the same vacuum pulling mixture into the cylinders. Carbs do not force the fuel in. Another is that we always recommend you keep the secondaries working at idle so they are pulling some fuel at all times. Equally we should remember that all these multiple carb intakes were designed for racing so they would all have had a direct linkage. Nowadays for the street we mostly see progressive linkages as they are easier to us. And we have had no feedback about so far about lean cylinders. I realise I have rambled, but I hope this helps.

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