The Stovebolt Site Forums The Shop Area Engine Shop 235 Dual Carburetor setup

I'm attempting to source some carburetors for my father's 1959 3100 Apache. He recently acquired a Thickstun dual carburetor intake manifold and we've been trying to determine which carburetors to use for his truck. The Thickstun carburetor mounting flange is a two bolt design (3 inch spacing) with a 1 3/4 throat diameter.

Everything we're finding research wise is recommending we use Stromberg BXOV-2 380269 carbs, including Mr. McGurk's performance book. However after power-walking all over the 2021 Pate Swap Meet, we couldn't find this carb, or if we did, it is a Stromberg with a three bolt mounting flange and two small throttle butterflies which seems to match the Ford Flathead intake manifolds.

What carburetors do you recommend that fit the two bolt (3 inch spacing) mounting configuration for a Chevrolet 235?

I don't know the spacing, but my 250 runs really good with dual Carter W-1's off 216 cubic inch engines.

The Stromberg BXOV-2 carbs are an S.A.E. size 2, as are the Carter W-1's mentioned by Joe.

Spacing is 2 11/16 inches.

Neither the Stromberg BXOV-2 380269 nor the Carter W-1 will fit to the manifold you have without either modification of the manifold, modification of the carburetors, or adapters.

In the "for what its worth" category, the only place on the 380269 carb where the 380269 actually appears is on the tag. How many tagged BXOV-2 carbs did you find?

And if your 235 is otherwise stock, then the answer to your question is .................none!

Jon.

Check with Langdons Stovebolt he is good at responding to phone calls. Also Mike's Carbs.

Just for conversation, got off the internet and checked our inventory. Out of more than 150,000 carburetors, of which more than 100 are Stromberg BXOV-2 units, of the 380269, we have exactly........none!

Jon.

Consider an alternative. Purchase a pair of adapters from Langon's Stovebolt Engine Company. Then obtain a pair of Holly/Weber 5200 carbs for a 1974 Ford Pinto. These are progressive two bbl carbs with a small primary and a large secondary. They are an excellent alternative to using a pair of one bbl carbs and run really well right out of the box. I ran those carbs for years on a Weiand intake. Make sure when you install them the fuel inlets are on the fender side of the manifold. The reason for this is that the main jets are in one end of the fuel bowl and installing the carbs with the fuel inlets toward the valve cover side of the manifold runs the risk of having the main jests uncover on hard acceleration and you get a hesitation. Installing them the other way has the fuel moving toward the main jests on acceleration as opposed to away from them.

The other thing on the 74 models is that the fuel inlets are threaded as opposed to a barb for hose and clamp on the earlier units. Otherwise, its the basic making up of some linkage, plumb the fuel lines, install some air cleaners.

You also might want to heat the bottom of the intake with hot water (Langdon has a tech tip on this and parts to help you). You may also want to covert the carbs to full electric choke, also see langdon.

Thank you for your comments thus far. I was hoping I asked a specific enough question without having to go into the often-repeated dissertation of which engine modifications have been done in order to justify our choice of a 2x1 manifold.

By accident, in our browsing for carburetor adapters among those suggested above, we spilled upon the fellow that is selling new castings of Thickstun branded equipment on eBay. Conveniently, it appears that he sells a carburetor adapter that adapts from a 2 15/16in 2 bolt mount to a 2 5/8in 3 bolt base which will allow us our choice of running the following carburetors: Stromberg 48, 81, 97 or a Holley 94. I incorrectly measured our Thickstun intake, it is not 3inch 2 bolt spacing, but in fact 2 15/16inch 2 bolt spacing.

After considering the alternative carburetors suggested above, we also found that the folks at Stromberg-97.com produce an improved version of the Stromberg 81 (which flows at 116CFM) which will satisfy the CFM requirements of our Chevrolet 235 if we use two of these on our Thickstun intake manifold. We were hoping to use a carburetor that would compliment the aesthetics of the era of the truck and their new Stromberg 81 fits the bill.

Finally, to answer CarbKing's question, we found two or three tagged Stromberg carburetors at the 2021 Pate Swap Meet, but none of them were the BXOV-2 model. We did find, however, one extremely crusty BXOV-2 missing its tag.

At this stage, it appears that we now need to buy just a few more pieces and we'll succeed on this 2x1 carb installation. Thanks Stovebolt forum, we'll see you around!

The Strombergs open all 4 bbls. simultaneously.
The 5200 Webers etc. are progressive, and operate on only the primary bbls. for start, idle, cruise with the secondaries only opening at larger throttle positions.
The Webers will probably have better tip-in response and low speed manners in traffic.

Quote "I was hoping I asked a specific enough question without having to go into the often-repeated dissertation of which engine modifications have been done in order to justify our choice of a 2x1 manifold."

Forgive me for bothering you with a question, that had you answered, I could possibly have given a good answer to your first question.

Quote "What carburetors do you recommend that fit the two bolt (3 inch spacing) mounting configuration for a Chevrolet 235?"

Good luck!

When I made the intake manifold for my 250, I built the carburetor bases for Rochester Mono-jets. Once I figured out they didn't perform like I wanted, I switched to Carter W-1's. The bolt spacing is different so I made offset mounting studs. All I needed was one for each carburetor. I simply cut a stud in two, off set the two pieces, and welded them back together. I then cut a spacer with the correct bore opening for the W-1, flared the bottom to match the manifold bore, and slotted one bolt hole in the spacer to clear the offset stud. The spacer is about 3/8" thick.