I have a 53 Caddy 331 currently sporting a single Rochester 4-jet. I have a Dual quad manifold for it, complete with a pair of Carter WCFB's. I have no linkage, and I'm gathering opinions on what linkage to run. The layout has the carbs situated like each carb feeds 4 pistons. Running progressive linkage would give really uneven flow paths for the fuel when not using both carbs. Running both carbs may be a bit much fuel for this thing, though. Any thoughts? I apologize in advance if this has been covered, I did search, but i may have missed it.
There are internal passages in the manifold. The primaries in the rear carb are what run the engine through these passages. Partial throttle opens the rear carb secondaries and then the front carb kicks in just before wide open throttle. Be carefull what you wish for, you might get it. Too much gas will wash your rings of oil and then you pop the motor. Hope this helps.
it is not a matter of too much fuel, unless there is something wrong with the carbs, it is too much air that without proper enrichment will cause the motor to stumble and bog.
If you have a standard 2x4 intake you can run a progressive set up and they will work very well . You usually set the rear carb up at about 65% throttle . You can also just use a block off plate on the rear carb and just run the front carb to save on fuel . Many 3x2 set ups are really only using the center carb to save on fuel . On a tunnel Ram , that is where the front carb feeds the front 4 cylinders and the rear carb feeds the rear 4 cylinders . If you run a progressive set up on a 2x4 tunnel ram then you will starve the rear 4 cylinders thus causing damage to the rear pistons because they are being run way too lean . What size carbs/cfm are you running ? On a 2x4 with a decent cam , a 450 cfm is usually plenty . If you are running 2--600 cfms that will be an awful lot of fuel going in that 331 Caddy engine ! Really 2--390's would be better . Yes the 2x4 multi carb set ups have that big Kool factor but a single good 4 bbl carb will serve you just fine . Just something to consider . Retro Jim
Absolutely not true. There are plenty of Dual quad,2x4 setups run straight up with no problems whatsoever. It's all about setting up the carbs correctly. Not all dual quad,2x4 manifolds are good for running progressive. But if it has a decent common plenum you'll be ok. All in all you can go either way most times . And really even straight linkage you can run it off the primaries and not see the secondaries till late in the game.
Read the first post-these are dual quads-not four two barrels. These aren't 97 strombergs. Hey guys, this ain't a pissing contest! In all likelyhood this is a factory dual quad set up with the WCFB's.
Most of the factory dual quad systems were progressive. The rear carb has the choke and operates as the primary carb. This is a 57 Ford factory intake with non-stock WCFB carbs. The original Cadillac and Chevrolet dual quads are set up the same way. These are setups made for the street and not really racing systems.
DEPENDING ON THE STYLE OF THE INTAKE MANIFOLD, THE TUNE OF THE ENGINE, AND THE SIZE OF THE CARBURETORS: either progressive or straight linkage can be made to work effectively. You did not specify which manifold you have. If the manifold has a common plenum area, then progressive can be made to work. If the manifold does not have a common plenum area (manifolds of this type are quite rare); then you would be forced to use straight linkage. Some of the earlier factory dual quad setups ran straight linkage. Later factory dual quad setups, especially on vehicles that might be raced, came from the factory with sufficiently large carburetors to support engine modifications for racing. These setups normally used progressive linkage. Today, FOR STREET AND SOME AMATEUR STRIP USE, unless we are RESTORING an original factory dual quad with progressive linkage; we suggest straight linkage. For race only setups, we suggest straight linkage. Benefits of straight linkage: better throttle response, better fuel economy. Benefits of progressive linkage: carburetor selection is less critical, and initial dial-in somewhat easier. Really, its your choice. Jon.
Sorry I corrected it, I meant 2x4, dual quads, just got my 2x4 and 4x2 mixed up at 6am. Like I said depends on the manifold and YOU CAN run straight linkage no problems, just set up the carbs. But really blanket statements that are wrong really don't sit well...
i've owned several cars w/2x4 intakes and getting ready to build another.i've used progressive on all of them.the first was a 56 chevy 210 coupe w/425 super wildcat buick engine w/t-10 4-speed.carbs were set at the factory and i made no changes except to hook up the throttle linkage to the carbs,second was a 65 ford galaxie with a 67 428 which i rebuilt and installed aan offy 2x4 hirise intake,it to was progressive linkage with the carbs mounted backwards(2 afb carters)work better than any set up i've used,the next 2x4 engine is going to be a studebaker 289(no its NOTa ford)brought up to r-4 specs.using a 2x4 intake(stock reproduction alum.)and a set of rochchester 4-barrels off a 283 power pac.
I've had 7 cars with dual quads, the only one that had progressive linkage was my 53 cad cpe de ville at 5200 lbs. it got 17 mpg highway. I was running 55 cad Eldorado setup with a batwing air cleaner
This may not help because I was running a BBC with dual quads. My mechanic set it up using 1 to 1 linkage. When I asked why, he said the front cylinders would run lean. On a SBC, no problems, but a BBC has problems with distribution. Anyway, a friend of mine with a '34 Coupe and 427 asked why my linkage was 1 to 1. I explained what my mechanic said so he tried it. It cooled his BBC down 15 degrees. The mechanic use to work for BDS before he opened his own shop.
Thank you guys for all the input. To answer a few questions, It is a stock Caddy Eldorado manifold. It does have a common plenum between the carbs. I'm using Carter WFCB's, which I'm told run about 450 cfm. The carbs I have are both primary carbs. I know that a tri-power has one carb with an idle circuit and choke, the other two only have primaries. Both of my carbs have idle circuts, and neither have chokes. I could use new carbs, but they'd look really dumb on the car.
Did they ever have chokes? I've owned a couple stock Cadillac dual quad setups, and both of them had choke mechanisms on both of the WCFBs.
Iv tries both stylis on my engine but with the progressive on an ford 302 it wouldnt run right, some rich some lean but with straight linkage and a lot of tuning all 8 plugs run even
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