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-   -   55.2-59 Dual Carb Intake for my 235 (https://67-72chevytrucks.com/vboard/showthread.php?t=821252)

Divine 59 04-29-2021 09:38 PM

Dual Carb Intake for my 235
 
1 Attachment(s)
My truck restore must sport this intake manifold.Attachment 2099007

So based on research I am seeing I need to start looking for Stromberg BXOV-2 carbs with a 1 5/32 inch venturi size.
Other possibles may be a Carter YF with a 1-1/4 inch venturi size.
Carburetor must bolt up on a 3 inch spacing (two studs).

If anyone has advice about going this route I would appreciate their comments.

Thanks for comments.

Steeveedee 04-30-2021 09:39 AM

Re: Dual Carb Intake for my 235
 
I have no carburetors for you, but that is one wicked cool intake manifold!

geezer#99 04-30-2021 10:22 AM

Re: Dual Carb Intake for my 235
 
Hey look!
A ‘thickstun’ intake.
Ran best sitting on the shelf.

Try here for carbs.

https://www.carburetor-parts.com/

_Ogre 04-30-2021 10:49 AM

Re: Dual Carb Intake for my 235
 
this ogre can't tune one carb, never mind tuning two of them
it is a good looking intake!

mr48chev 04-30-2021 10:55 AM

Re: Dual Carb Intake for my 235
 
I had some of that style of Stromberg in the school shop for the kids to take apart and put back together when we were doing the section on Carburetors. They are fairly simple to work on and come from mid 30's Dodges among other rigs.

They look like this one that is missing parts https://www.ebay.com/itm/Stromberg-1...-/184667901201

Here's another one with better photos. https://www.ebay.com/itm/STROMBERG-B...-/113713091637

I'd think if you got to a decent swap meet and found the old Mopar guys you could find some and probably find a matching pair. You just need to do your homework and know exactly what you are looking for.

1project2many 04-30-2021 03:12 PM

Re: Dual Carb Intake for my 235
 
Many of these old manifolds were built for kids racing on street or track. Few designs had significant testing or engineering. Multiple carb intakes added some power by adding another path for air and by separating (in some cases) the intake from the heated exhaust. Folks get very excited at the chance to run a unique, cool, or pretty manifold but end up with a number of compromises after doing the work to install the parts. I have a few of those T-shirts in my own collection.

I am a big fan of EFI as a way to overcome deficiencies in manifold design. You will not make a bad manifold good using EFI but you could make your engine more driveable by using a computer to compensate for temperature and pressure changes with much more accuracy and speed than a carb and distributor.

If your build allows maybe you would consider finding or making two throttle bodies that could be used on top of that engine instead of carburetors?

mr48chev 04-30-2021 05:41 PM

Re: Dual Carb Intake for my 235
 
EFI is nice but that doesn't fit his build plan. I doubt he is building it with the intent of it being a "reacher" for the long roads on a regular basis.

Sometimes the cool factor just flat outweighs the concept of being most practical.

Divine 59 04-30-2021 10:00 PM

Re: Dual Carb Intake for my 235
 
Gee, thanks for the encouragement, I think? Maybe I should stick to buying t-shirts instead of parts for my truck to make it how I want. I do appreciate the help from people that offer sources where I can do some research, learn and try to achieve my goal.

Maybe I should focus on learning from Inliners, and the Stovebolt forums.

Rickysnickers 05-01-2021 09:24 AM

Re: Dual Carb Intake for my 235
 
Quote:

Originally Posted by Divine 59 (Post 8915447)
Gee, thanks for the encouragement, I think? Maybe I should stick to buying t-shirts instead of parts for my truck to make it how I want. I do appreciate the help from people that offer sources where I can do some research, learn and try to achieve my goal.

Maybe I should focus on learning from Inliners, and the Stovebolt forums.

No, stay here. There are some that have differing opinions. If you don't like them, just ignore them and keep going on with your build. Different stuff is always good to see!!

nvrdone 05-01-2021 11:47 AM

Re: Dual Carb Intake for my 235
 
building a truck is not always about being effeicent or practical. sometimes its about building exactly what you want and using really different cool parts. If you dont agree with them, ignore them. remember opinions are like back sides - every one has one.

mr48chev 05-02-2021 11:39 AM

Re: Dual Carb Intake for my 235
 
Quote:

Originally Posted by nvrdone (Post 8915602)
building a truck is not always about being effeicent or practical. sometimes its about building exactly what you want and using really different cool parts. If you dont agree with them, ignore them. remember opinions are like back sides - every one has one.

I can't say it better than he did.

As long as you build a safe truck with nothing designed into the build that causes safety issues build it the way you always dreamed of building it.

Having a period correct engine right down to the Very rare (serious high bubba points) intake and correct for the application carbs and air cleaners and other pieces that all work together as one cohesive unit is a feat in it's self. That engine will get a lot more attention and photos taken than a much more efficient but very boring engine with FI.

Truthfully I am wanting to see the whole build as I am hoping the whole truck is a period correct build with the proper pieces that set it in a certain time frame and all the components compliment each other.

mick53 05-02-2021 05:49 PM

Re: Dual Carb Intake for my 235
 
I would rather be cool and slow than fast and uncool. Chrome won't get you home but it might get you a ride from the side of the road. Plus you will look cool. I used to spend more time on Stovebolt but I got tiered of being ridiculed for my less than conventional ideas. I welcome different points of view but there is no reason for being rude. Just do your thing it's your truck. No rules!

1project2many 05-02-2021 06:46 PM

Re: Dual Carb Intake for my 235
 
Quote:

Gee, thanks for the encouragement, I think? Maybe I should stick to buying t-shirts instead of parts for my truck to make it how I want.

Hmm... I think you misunderstand. You're welcome to build it however you want. I'm not telling you any differently. But you said this:
Quote:

If anyone has advice about going this route I would appreciate their comments.
I am suggesting that the manifold has compromises that may cause your driving experience to suffer. As someone who has played with a bunch of "ain't never gonna work" parts I've had my share of successes. I've also had more than a few vehicles that require *special treatment* to make them driveable without a bunch of extra effort.

I've got some experience playing with multiple carb manifolds. If you want them to run right it often takes some work. Granted, it seems less like work when you're excited about it. But those old Strombergs came in a bunch of different sizes and a couple of different configurations. It's possible 60 years after they were made to get different size carbs or carbs with mismatched parts. Might work with a single carb but you really want a matched set. Get the wrong combination and you could end up chasing carb popping, lean cylinders, and overheating. And it's possible you end up on a quest to find your tail. Doesn't mean you can't or won't find a matched pair. But it does mean you should become at least proficient in speaking Stromberg if you're set on the BXOV.

Carter and Rochester also made two bolt flange carburetors that are likely to fit that manifold. BXOV-2 uses a size 2 SAE flange which was common on smaller sixes. SAE2 flange reportedly has a bolt hole center to center distance of 2 11/16". Rochester Monojet carbs suffer from distortion and throttle shaft wear and can be hard to tame at idle or just off-idle. Carters were super reliable and simple imo. I run one on my '36 Plymouth and it only takes me about 15 minutes every spring to remove the top, clean the bowl and jets, reassemble, and move on to points check and adjustment. Like the Strombergs many of these carbs are 40 years old or older and may suffer from wear, parts mismatch, corrosion issues, or mechanic damage.

Now with multi carbs, once you get a matched set you will still have some compromising to do. How it affects you really depends on how you use the truck and how much the weather changes around you. That manifold was designed to help improve power at WOT on a warm engine by increasing available airflow and by keeping the intake air cool. With no manifold heating you eliminate most of the fuel vaporization that benefits low speed and idle operation. If you're running original compression ratio and stock heads you're looking at designs that don't really help the fuel mix or burn well. Fuel was crap back then and the I6 was designed to slow combustion and prevent detonation and overheating. This might not be a problem for you but if you have damp days in your area or if the weather can be cool one week and hot the next or if you like extending the car season as long as possible then you may end up with the carbs running on the rich side to help make it drive better on the bad / cool days. Generally running the engine richer can increase chances of fouling a plug and diluting engine oil and it can lead to carbon bits dumped on the back of your truck each time you go out for a drive. If you like tweaking carbs and timing you will likely invest time in making the carbs behave as close to perfect as you can get them. Now I don't know how much carb experience you have and I don't know how much you like the idea of playing with carbs. I'm just offering advice and comments based on my experiences.

I mention EFI because I've found that computers have a far greater range of adjustments than were available on most carb and distributor setups and they can be made to do really great things for an old engine. Tuning EFI requires more initial work than a carb setup and requires a bunch of learning but once the system's dialed in it really does a great job of covering a wide range of operating conditions. If you are the kind that likes tweaking then EFI systems can offer you a *lot* of opportunity to make changes and try new settings without getting your hands dirty.

If you want to go with carbs I'd recommend trying to find an old manual that does a good job explaining how the carb of your choosing works. Some of the old GMC engines came with Strombergs. Studebaker loved to use Strombergs. A "unit repair manual" or a factory service manual is likely to have detailed information for those technicians that wanted to do a great job.

For overhaul kits and parts for my old carbs I love using vintage carb kits. "New" kits are usually lacking in parts and tools required to do a thorough job. Old paper gaskets can sit for a day or two in a pan of WD40 and they'll become nice and flexible. Downside to old kits is they generally use rubber parts. If your truck is likely to see E10 or higher ethanol content I would advise trying to find Viton parts where possible to replace the rubber. I would also advise wherever possible to reduce occurrences of dissimilar metals in your fuel system. Ethanol sucks in water. Ethanol and water are highly corrosive. Put an aluminum carb, brass floats, and steel lines together with water and ethanol and you will see aggravated corrosion. Sucks. I have to deal with it all the time.

Quote:

Having a period correct engine right down to the Very rare (serious high bubba points) intake
Are you sure that one's original and Very rare? Looks very much like the repops sold on Ebay. None are listed now but here's a thread on the HAMB from 2009:
https://www.jalopyjournal.com/forum/...intake.340747/

edit: FWIW I absolutely love hiding EFI under vintage parts. A Rochester Monojet body would be a great place to hide a fuel injector. Plumb fuel line to each carb from a Y fitting on a hollow fuel pump and you have a great conduit to hide injector wiring. Use the body of the pump as a location to hide a small MAP sensor and run a vacuum line down from a Tee so it appears you have an operable vacuum assist pump fuel pump. Throttle position sensor could be build from a Ford throttle pedal which has the TPS already installed. It's likely the coolant temp sensor would have to be visible but it may be possible to disguise it as a vintage sensor for the gauge. Relays, power connections, and ECM could be placed under the seat. And if you don't want to install an EFI compatible tank you could hide a fuel pump reservoir under the truck on a frame rail.

lv2tri2 05-02-2021 08:58 PM

Re: Dual Carb Intake for my 235
 
Quote:

Originally Posted by Divine 59 (Post 8915080)
My truck restore must sport this intake manifold.Attachment 2099007

So based on research I am seeing I need to start looking for Stromberg BXOV-2 carbs with a 1 5/32 inch venturi size.
Other possibles may be a Carter YF with a 1-1/4 inch venturi size.
Carburetor must bolt up on a 3 inch spacing (two studs).

If anyone has advice about going this route I would appreciate their comments.

Thanks for comments.

Years ago I put two Carter W-1s on a GMC 228. I didn't know how to tune them but that motor ran very well and the increase in power, (extra fuel, extra air, what ever) was amazing. Best of luck.

mr48chev 05-03-2021 12:55 PM

Re: Dual Carb Intake for my 235
 
2 Attachment(s)
Shot of Pat Ganahl's 1948 Hi-Tork block and cast iron Wayne (WMD 225) head with three BX0V-2 carbs for inspiration.

Volfandt 05-04-2021 07:44 PM

Re: Dual Carb Intake for my 235
 
1 Attachment(s)
Cool intake. It'll look great on an old 235 or 261 stuffed into an AD truck......
I run my 49 235 w/dual carbs year round and enjoy every minute of the cruises.
I tried dual Roch B's but wasn't happy with them.
I was going to try dual Carter YF's when I decided to give a pair of 2bbl Carter Webers 32/32 a shot.
I'll not go back, LOL.

The math and it's many adherents say running dual carbs won't work right on a poor flowing Stovebolt 6. Well, if you don't mind spending some time fine tuning your setup you can get it to perform as good or better as any single carb or similar fuel delivery system and do it reliably....

Build to your tastes and visions.

Carry On.

Divine 59 05-05-2021 09:31 PM

Re: Dual Carb Intake for my 235
 
So, for now I will tell you what I have learned.
1) there is a carb adapter made for this intake that allows the use of Stromberg carburetors.
2)My research has led me to consider using a Stromberg 81, which flows 116 cfm. I think two of these new carbs will be a good starting point to begin tuning.
3) I can purchase brand new Stromberg 81s from Stromberg-97.com. They are pricey but I will be not be working with air horns and parts that are many decades old.
4) If I need to add fuel or remove fuel I will determine this by using a bung mounted Air/Fuel gauge and to assist my tune after the carbs are synchronized.

I guess y'all can watch and tell me "told you so" if I fail. But I am determined to try and I think I will succeed. Time will tell.

Steeveedee 05-05-2021 10:26 PM

Re: Dual Carb Intake for my 235
 
You'll be fine with a little tweaking and a vacuum gauge. I worked for some Chevrolet dealers in the early '70s and will never forget that '32 Chevy coupe with the 348 and 6 Stromberg 97s on it that was a trade-in on a new car, as long as I live! :chevy:

1project2many 05-10-2021 05:15 PM

Re: Dual Carb Intake for my 235
 
I'm surprised no one else has answered by now.

This is not about watching you fail. This is more about trying to help you make choices the help you get the performance you want. It sounds like you've got a good start at this point.

In case you don't know, there are wide band O2 sensors and narrow band O2 sensors. Make sure the gauge you get uses a wide band. Narrow band sensors are much less expensive but they quickly lose accuracy when afr moves away from stoich.

I think you have a good idea in using the new parts. You should also get some support going through that site. Use the expected HP curve of the engine to calculate carburetor size. Use the expected torque curve to help select jets.

Try to learn whether the accelerator pumps can be adjusted or changed. On an I6 with small ports and low flow it is possible to dump too much fuel during acceleration. Not likely but possible. It's also possible to have pumps that are too small. Not likely with those carbs but again, possible.

Your engine may also benefit from a more aggressive spark curve. The faster you can get engine rpm to increase the lower the chance for fuel to condense on the manifold walls. Seems silly but it can play hell with tuning.

Good luck. Please keep us posted.

Divine 59 05-11-2021 07:00 PM

Re: Dual Carb Intake for my 235
 
Thanks 1project2many, I have the carb spacers. The next item will be the carbs, but it will take a while.


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