anybody know how to set them up,should i use straight or progressive linkage and what about the vacume for all 3 and so forth,im not sure about it cause this is my first time with multiple carbs,i have heard of a lot of different things so any help would be great . thanks
you should join in liners international and find the article by K. Patrick Smith on setting up multiple Rochester 1 barrels. Vacuum for the distributor for the distributor only needs to come from one carb, if you are using the stock exhaust manifold, make sure the heat butterfly is operating properly, if using aftermarket such as fenton u MUST have heat to the bottom of the intake manifold or you will always have a fat sloppy rich running carb set up. very very important on 3x1 applications. try using a gmc lower thermostat housing with the water outlet on the driver side plum to a plate under the intake manifold with a return back to your water pump or heater system, this will provide the heat needed to properly atomize the fuel. If you want something a little more exotic, try 3 pinto weber progressive 2 barrels put the same deal with the heat to the intake, see tom langdon at stove bolt engine company for purchase of carbs adapters and set up advice he is the best around.
I'd only use straight linkage if the engine had a pretty radical cam, and you have deep gears in the rear end, where you could actually use that surge of fuel. For an everyday driver with light mods, go progressive. As stated above me, vaccum only needs to come from one carb. You will need to learn how to sync the carbs. You can buy a carb sync tool from a British car restoration place like www.victoriabritish.com it's kinda fun synching them. I used to have a ton of British cars... you learn all about synching carbs when you own one of those things... Be sure to post pics of your setup! Inline sixes with multiple carbs are not only cool and different, they are pleasing to the ol' eyeballs.
keep me posted on this project as my 57 has a 235 as well, when i got the car gosh 30+ years ago from my father when i was 15 it ran a 24 in the quater mile, it now runs a 16.4. i love my motor and my car so its great to see some one w/ my passion for the stright 6's
Gotta ask....but why 3 carbs? I'm currently running 3 my 235 they are rocherster bc carbs, set it up with progressive linkage, runs great with the center, and there's a little more when i open it up, but i'm actually switching back to 2 carbs, ran better with just the 2 carbs, 3 are alittle over kill in my opinion, but it's a stock 235 with the exception of the fenton split.... The last pic was what i had on it, seemed a lot more powerful, but i had issues with the carter W1's, and got pissed and put the offy 3x1 on. 3-4 years later and different carbs on the ellis intake and that will be back on the car sometime in nov. What are you working on car/truck? on my 54, i had to do some heavy modification to the rib on the firewall to fit the back carb in and then had to move some wiring so the carb didn't hit it.....now i'll be pissed when the 3 carbs are off and i have a screwed up firewall from them....
I run progressive tripower Rochesters on my 261. I used to have it direct when it was on a 235, and it never ran right. I made my own linkage, as there isn't anything available, and I modified the end carbs to just be dumpers, just like the factory did on 348's and Olds J2 setups. Can't hit the ends until you get up to about 2200 rpms or so, or it will bog a bit, but I'm still happy with it.
Progressive carbs don't have to be synchronized (vacuum gauges, Uni-Syn, etc.), they just have to kick in and reach WOT at the same time, no vacuum comparo needed (that's for separate carbs on separate manifold runners only). It's just linkage. Dual carbs have an advantage: the placement of the carbs is closer to "centered" between the cylinders, and distribution is probably better. The problem is that the response is going to be based on a big pump shot, rich power valve or some other compensation for the big increase in air volume every time you roll it on. A progressive can live with nearly stock jetting in the primary for low speed.
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