Choosing the right linkage for your 4×2
Hot rod 4×2 intakes come in many forms, but most put the carbs in line behind each other or staggered in a 2-plus-2 square arrangement. Some are widely spaced to get the carburetors right over the intake ports, with a big single plenum chamber, like the famous Horne/Cragar intakes, but some have a very close, overlapped stagger like the Weiand WC4D manifold for small block Chevy, which is more of a dual-plane design.
4×2 in line – direct.
Pretty much all the early Flathead Ford intakes, plus a few early ohv intakes, put all four carbs in a line, like a typical 3×2 but with one more 97 squeezed on the end. The main brands you might see are Sharp and Weiand. Building a 4×2 direct linkage so all the carburetors work at the same time is simple. Just order up 4 of our 9091K kits (Superlink lever arm and swivel) and link them together with a straight length of 3/16th rod. You might want to order some of our 9054K Snapback torsion type carburetor return springs, too, but that’s pretty much it.
4×2 in line – progressive.
Building a 4×2 progressive linkage is trickier. We can build these to special order, though, and here’s how. We put our 9096K long levers on the two center carburetors and link them together with a short threaded rod between two rod ends. We then link the second carb to the front one with a sliding link, and the front carb back to the fourth, just like a 3×2 progressive system. Email us at email@example.com if you need one. Just remember: As with most progressive systems, if you want to use banjo fuel fittings, you must add our Banjo Fitting Spacers (9086K) to move the fuel line away from the long center levers.
4×2 staggered systems.
If your intake manifold spaces the carburetors far enough apart across the intake to get separate linkage rods to each bank of carburetors, all you need is a quality, sturdy linkage that won’t flex when you stick your foot in it, and won’t swamp your beautiful 97s with huge pillow-block brackets either. The Stromberg 4×2, designed and manufactured exclusively by us, fulfills all those criteria with a whole new level of quality, efficiency and looks.
4×2 staggered systems need a direct (non-progressive) linkage, otherwise some intake ports (and therefore cylinders) are going to end up lean and other rich.
Stromberg offers one type of 4×2 direct linkage, but in two sizes. You can find them on this website, of course. Kit 9271-D is ready made to fit the Offenhauser Pacesetter 5024 – Chevy 4×2 intake – which spaces the carburetors 8-5/8th inch in front of each other and 6-1/2 inch apart across the intake with 3/4 inch offset between the two banks of carbs (ie. the one bank is 3/4 inch in front of the other). This linkage is ready to go, comes almost completely assembled and even though it bolts straight on, it still comes with full instructions, of course.
If you have any other intake of this type, choose our kit 9270-D 4×2 Trim-to-Fit Kit. It will work with intakes that space the carburetors up to 9-1/2 inch in front of each other, the same dimension across the intake and with 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.
The Weiand WC4D manifold – and others.
We mentioned the Weiand WC4D manifold, above, which sets the Stromberg 97 carburetors in a sort of in-line, overlapped stagger (!) The Edelbrock CD-694 for early Cadillac engines is another example, as are most blower plates for mounting 97 carbs on GMC-style superchargers. All of these place the carburetors so close together that you cannot get a linkage rod between the two banks of carburetors. What you need for these intakes is two of our 9139K Throttle Shaft Extension Kits (comprising a stainless steel shaft extension with a separate support bracket) plus four 9091K SuperLink arm and swivel plus a length of 3/16 inch diameter rod to join them all together. You’ll find these on this website under Linkage Parts. And there’s a full ‘How-To’ article here too.
Your link to the pedal.
Stromberg recommends a mechanical pedal link for all multi-carb systems. Ideally, your 4×2 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. The 9096K lever can also be drilled and pinned to the Back-bar to ensure positive location.
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