The Stovebolt Site Forums The Shop Area The HiPo Shop 235 w/ duals and 3x1.......

Hey guys i'm wrapping up the engine for my 54, and am at the carb faze. Now i've read up alot on both here and inliners on the 3x1 setup. my plan is pretty much to make my own progressive linkage where the outter carbs open up just slightly after the center. the carbs are all rochesters from a 62 chevy truck, and i'm putting fresh rebuild kits on all 3 tonite. I plan on running vacumn from the center carb only to the vacumn advance and plugging the outter two carbs vacumn ports. the fuel is coming from a 1 into 3 fuel block mounted on the firewall with regular old 3/8 rubber hose to the carbs. from the pump its going via aluminum line to a glass bowl filter and into the fuel block. i plan on driving this thing up to the daytona turkey run in 2 weeks so it's crunch time. I also made a couple of block off plates for the outter carb holes on the intake just in case i can't get the system working good in time, i'll just drive up on the center carb.

so for you all that know these setups tell me what you think of my plan, and give me any input or ideas you might have. i need all the help i can get!!!! tks

as far as the engine its .40 over, stock cam, completly rebuilt head. still running points dist. and i plan on running straight duals from those black headers. sitting behind it is a T-5 with 3.08's out back. it likes to cruise at 60mph around 2,000rpm

http://i121.photobucket.com/albums/o235/marcelo54/puravida039.jpg

http://i121.photobucket.com/albums/o235/marcelo54/puravida035.jpg

http://i121.photobucket.com/albums/o235/marcelo54/puravida034.jpg

Nice looking engine, I like the green. I will say this...I didn't think that setup would physically fit into the engine compartment without hammering a cavity into the firewall for the back carburetor. Have you confirmed it will fit or have you anticipated massaging the sheetmetal.

I had this same setup on a 235 in a car (it fits in a car). I didn't use the Rochesters. I used three matched Strombergs that are quite a bit smaller (venturi) than the Rochesters. I can't imagine how progressive linkage would work on this setup...mine were all tied together and worked beautifully. Keep us posted on your progress.

Stuart

i was told a progressive system would be better on tuning and mpg. is this not true?? if all i have to do is tie them up together that will make my life way simple.

as far as the clearance i've seen it done beofore. i most likely have to remove the drivers fender support rod though.

another question i thought about, i was originally planning on mounting my fuel block to the front drivers side of the valve cover, which would make running the lines much simpler and clean up my firewall, but someone mentioned if i have the block so close to the exhaust i might get vapor lock from the fuel heating up. what you guys think?

Are those carbs matching calibration numbers? I notice only one of them has an automatic choke, and that one would logically work better in the center position, with the chokes on the outboard carbs locked in the open position. You will also need to do something to disable the idle system on your outboard carbs, adjust the throttle plates to completely block the airflow when the throttle is closed, and don't even think about opening the extra carbs until you're at 3/4 throttle, or maybe more. You're still going to have a massive case of over-carburetion when the outboards open up. If the system works at all, you need to have a very rapid opening as the center carb approaches wide open, similar to the old Pontiac Tri-Power, or the Corvair 4-carb system. BTW, the auxiliary carbs on both of those applications had NO idle system whatsoever. They only worked at wide-open throttle.

Be absolutely sure that at least the auxiliary carbs are identical in jetting and other specifications. It would be a much better idea to put blind spacers under the outboard carbs where they can't flow any air, and just run them for visual effect.
Jerry

These are only my unprofessional opinions...I don't think vapor lock is a concern. Mount the fuel block wherever it looks best to you.

If it were me, which it isn't, and I was bound and determined to run three carburetors, I would spend some time to find three matched units in a very small venturi size and run them off a common linkage.

To be honest, your engine isn't modified enough to support three carburetors, again, my opinion. A overbore without some head work and an accompanying cam doesn't support the added fuel.

Two carburetors is pushing it and three big fat Rochesters will drown you out. If you want to run three functioning carburetors, they need to be as small as you can find. This won't be cheap! Maybe the best plan would be as HRL mentioned, block the two outboard carbs off and run only the center.

I sure don't want to rain on your parade, but having a setup that might be designed for failure is not going to make you happy.

Jon (carbking) has the expertise here...give him a call, or maybe he will see this and offer some advice. Keep us posted and good luck.

Stuart

I am agreeing with the others here.Three carb's on a stock motor will be a BIG disapointment.Unless you are putting a better cam in it.

Was any extra work done when the head was reworked and is it an 848? What year is the motor? I started with this same setup and couldn't get to a nice matched set of Rochesters (I have a box of like 20 somewhere) I rebuilt several, they all leaked...

This was on a 58' 235 30 over with a 3/4 cam. I ended up with split stock exaust and the 3X intake with Langdon's Carter/Weber setup. and an HEI Dizzy. It ran great backed by an S10 5 speed and a 3.90 Rear..

Your setup should run good I think if you get the carbs setup right. The progressive will be a trick but is do'able. Clearance on the rear carb is gonna be close but can be done. You will lose that support rod, take em both out.

Like you said worse case you can put your blockers in and run it for looks, but you know that's not as much fun. Enjoy it that way, save up and add the cam and you'll see a difference.

Mongo

lol you guys sure rained on my parade. well i was anticipating to run into problems from the start with this set up so i'm not surprised. The rochesters are not all identical numbers but are all from 62 chevy trucks. i'm removing the choke from the one carb that has one. i'm in miami and i've never ran a choke on any of my carbed cars no need. As fas as the 3x1 setup i ran into the intake for close to nothing and figured i'd give it a shot. the head just had a rebuild no port work and the valves are standard, and its not a 848 head. the block numbers put it as a 1956. i'm not looking for power just looks. so worse comes to worse i'll block the carbs and run the center.

so overall later on you guys recommend going to a 2x1 setup instead and ditching the rochesters for what????? i see the landgoon webers but they are $85 a piece, plus 2 to 1 adapters plates, plus dual linkage plus a offy 2x1 intake i'd be into it for $500. way passed my budget. are there any single barrels i could possibly buy new and just get a used 2x1 intake off ebay and make my own linkage???

The 3-carb manifold just oozes "cool". Just fake it with two dummy carbs on the ends and 95% of the people who look under the hood will never know the difference. One carb is always better than multiples, unless you're planning to run the RPM at the ragged edge of disaster all the time, and the rest of the engine is built to take advantage of the increased airflow.

There's no substitute for cubic dollars- - - - - -how fast can you afford to go?
Jerry

doesn't support the added fuel ... Two carburetors is pushing it and three big fat Rochesters will drown you out.

Whats wrong with this picture?
Carburetors don't add fuel.
They add air.
Engine vacuum adds fuel.
Too much carburetor = not enough fuel.