The Stovebolt Site Forums The Shop Area Engine Shop Unknown carb to 1954 intake manifold

I have a question regarding an unknown Rochester carb that came separately with my truck. The engine is a 1954 235. I recently purchased a 235 carb gasket and it fits great on the intake manifold insulator(?). The gasket has four channels radiating out from the main hole that end at the four small holes in the intake manifold top. However when I put the carb on, it fits on the bolts correctly but I see that the carb base has two “cookie cutter bites” that don’t cover the gasket in two locations ( where two of the radiating channels ending in small holes in the intake manifold top). Am I to assume that this is not the normal combination of carburetor-intake? The carb has a flange where the air cleaner hooks to it so I am assuming it is a later Rochester. It doesn’t seem to have any numbers on it other than RP and GM. What carb would be the correct one and does anyone have a spare? And does anyone need the one I have (seems to be in good condition, maybe rebuilt)?

Picture is better than 1000 words

Sstock, I have trouble posting pics from an IPad. I have some on my phone if you can send me an email address. That seems to work better. Thanks. Maybe Carbking has an answer too.

Just found a number on the base. 7005608. Any help?

Hey Snowman , I Googled that number and it came back as a "base" used on a 261 Chevy, Rochester Monojet , do not know if that information is correct but a picture is worth a thousand words. Try copying and pasting this url into your browser and see if you can find it within the site. Hopefully Jon (Carbking) will see your post and chime in.
http://www.carburetion.com/r1.asp#R1M

What year 261 carburetor?

There were at least 2 styles of 54-63 235/261 truck carburetors (more 235 styles if car carburetors are included):
- one style allowed attachment of the air cleaner with a clamp around the base of the air cleaner - clamp around the "throat"
http://www.carburetion.com/images/carbid/r1-bc.jpg

- one style allowed attachment of the air cleaner with a center post above the "throat" of the carburetor
http://www.carburetion.com/images/carbid/roch1.jpg

You might want to indicate if your carburetor appears to have a manual choke or an automatic choke.
center carb here: http://www.carburetion.com/images/Inventory/R1carbs.jpg

it has a manual choke. It has a “flange” where the air cleaner attaches (throat?).

Dusty53: I tried your link. Searched in that link. Did not get anything. Can you detail what you did on that "CarbsUnlimited" Website to get your info? Thanks

SNOWMAN: Do not worry about the skives (bites) on the outside perimeter of the flange. Those are clearance for a screw and driver while assembling the body. Just be sure your gasket does not block the small hole near the big hole.

From search on Stovebolt: Your era used 7004468 for 235 and 7005140 for 261. The CarbsUnlimited website list both of these carbs for 235 and have the same rebuild kit. R1-B carbs.1950-1959, hand choke.

LOOK FOR just 4468 or 5140 on carb flange or any 4 digit number. The 700 was left off sometimes.

Bartamos: Thanks for the reply. The flange I’m talking about is on the top of the carb. The “bites” I see are in the base, not the flange on top. I’ve seen carb bases that go on the 235 that have an oval shape outer margin. This one is has two curves into the margin, exposing the gasket as I look down when the carb is mounted and two of the four small holes that surround the major hole in the insulator show. Is that normal?

Once again, the two curves are for access to the screws that hold the body on. The gasket is not made with those because you assemble the carb before the gasket goes on. There is still enough lip on the carb base to seal on the gasket. As I said, do not worry about that visual you are getting there.

"two of the four small holes that surround the major hole in the insulator show."
All I have seen is a gasket with two or four radial slots and a phenolic spacer/insulator with part-way-thru radial slots. Right now I don't understand what you are seeing after all is assembled. Is your insulator upsidedown? You will have to post pics of your assembled stuff now. Sometimes people send pics to tclederman and he posts them. Maybe he will offer. If you have pics on your computer, you can post when resized to 300MB or less. Use the attachment manager below left of posts..

You could be having an issue because you have a "small" hole intake manifold, a "large" hole carb throat and a mix of gasket/insulators which don't allow synergy.
If you only have one gasket, it goes between carb and insulator. Slots, partial slots and little hole should align so little hole has a passage to inside air/vacuum.

Thanks for all the info. I’m trying to sort it out. I think you may be right- mixture of carb base, gasket, insulator may be the problem. The style of carb is the one with manual choke and with a place for a center post like Tim said. I sent pictures to DADS50; he said he’d host them. Hopefully he’ll get them and send them along. Again thanks again for all the help.

Your e mail had not shown up yet

I don't think the manual choke or air cleaner attachment have much do to with the issue here. It's the bottom/manifold interface we are talking about. Now that I posted a picture and you know the "bites" are normal and it physically fits, What is keeping you from using this carb/moving forward? Your air cleaner won't mount?

Just checked the bottom base of the carb. It has a stamped 15013 on the bottom. I put it on with a gasket from Classic Parts that has the four radiating channels from the big hole in the middle and it fits -almost. Just the very tip of two of the small channels ending in small holes of the gasket stick out. Put the smallest glob of RTV in the gasket holes at the end of the two radiating channels that stick out from the carb base-manifold ( like 1/4 size of a pencil eraser, just to block air from getting in under the carb base) and it seems to seal everything up. The diameter of the large hole in the base and the manifold match so I am assuming it’s for a 235, not a 261. Now to hook linkage, vacuum line, and gas line up ( oh yeah I’d better put the cleaned gas tank back in and hook it up, put some gas in!). The next challenge is a wiring harness that keeps calling my name. Then should be ready to fire up.

"The diameter of the large hole in the base and the manifold match so I am assuming it’s for a 235, not a 261. "

Why that assumption?

I have "interchanged" 1954 235 carburetors with later 261 carburetors.

https://www.classicparts.com/1954-62-Carburetor-Base-Gasket-L-6-235/productinfo/81-210/

7015013 is for a 1960-1962, 261 engine.

carbking at the carburetorshop

more carbking info

Tim, I think he is saying that because of what I said about big hole/small hole. I was under the impression that even though the mounting hole spacing is same for 235/261, that the actual throat hole in their carbs/manifolds were different....but they still interchange. It's a mixmatch that still works OK. Let me know if this is right or wrong.

bartamos,

I am not sure about the mismatch of the "throat holes", but the mounting bolt holes were the same.

Nonetheless, I'd use a 261 carb on a 261 engine. In a bind, I'd use what works.

Agreed.

Thanks for all the information on the carb-manifold thing. All I am concerned about is if this combo will work. I was given the carb when I bought the truck. The guy said it didn’t originally come with the truck, but “since it’s a single barrel Rochester it would work”. The engine/manifold is a 1954 235. He said it should work. I really would like to trade this carb for a carb that went with this engine. I also have been considering getting a Carter 2100s, which I’ve heard will fit the 1954 235 engine. Anyone want to trade? If not, will this combo work?

If I understand this deal. Your manifold inlet should be smaller than the 261 carb throat. This creates a "step" in the air flow. A 235 carb on a 261 manifold would seem better because the step does not block air flow. Folks have used this second scenario with OK results. Don't know if it would run OK or not. You can't swap, buy or sell on this forum. Use the proper forum on Stovebolt for that. Buy a 235 sized B1 carb and proper gasket and put it on. The RTV thing is NO GOOD either. Please post the part number of the gasket and insulator you got from Classic Parts.
Classic has two different carb gaskets with radial slots and two different insulators, they all say 1954, so you may have purchased the wrong ones for your setup....but what you are trying to do may be a bad idea anyway so wait for more info/advice.

Something is screwed up here. You say "holes match". Carb throttle bore and manifold inlet diameter? You say the manifold is 235. The carb comes back to 261. What "holes" are you talking about? Mounting holes or big hole in carb and manifold? The 235 and 261 carbs are 1/8" different ID's???????? (1 9/16, 1 11/16)

Carbking will straighten this out soon.

Not related to whats going on here


I once purchased a carter for a 235 wide spacing

Only to find out someone put a smaller base on it

Mixed up parts....

I’m trying to sort the mystery out. So I went out to the truck to check the numbers. I mic’d the bores. Here’s what I have.

Bore of intake manifold-1 11/16”
Bore of the carb base-1 11/16”
Intake Manifold cast numbers-3835580 GM on the left side, 24 on the right side.
Bolt centers-2 15/16” center to center
Carb lower side of base-7005608 (faded)
Under carb base-15018
Upper side of carb base-6
Engine-0329620F54X
Head-3835913 GM1

I am very appreciative for all the help sorting this out. I will continue on this quest for a running AD Chevy. All advice is welcome.

F 54 X
F = Flint Michigan engine plant
54 = 1954 assembly year
X = 3100 truck

3835913 = 1955 head
What is the head date casting code: under valve cover on manifold side, between valves 4 and 5?

Bartamos - I did a Google search and it led me to the Carbs Unlimited page , not sure exactly how I did do that but I was hoping to give Snowman51 something to "look at" and compare. Here is a page on the CU website that has the Rochester B and the Monojet on a page. I would have responded quicker, but I've been out of commission for a few days.

http://www.carburetion.com/CarbID/RochesterID.htm

Even though you have mis typed the base number 15018 (was 15013), I believe you have matching bores of a 261 carb and manifold and the wrong gasket and/or insulator. I DO NOT know if you have a 235 or a 261 motor.

Ronnie, I agree it is a 261 base. When I google 7005608 I don't get anything. When I go to the CarbsUnlimited link and use their search button on that number, I don't get anything. That's all I was saying. Just my confusion. No sweat. When I google Rochester 7005608, I do get to Carbs Unlimited.

7005608 is mentioned here - 261 carb base

http://www.chevytalk.org/fusionbb/showpost.php?post/2101520/

I did see that Tim. As you said in a post I also saw, early 235 carbs fit 216. So that fact and the fact that 235 and 261 fit each other, and the fact that their carb sections interchange, makes B1 carbs a real challenge to identify and I now give up. Measurements and a base number is all we have. Other numbers are cast numbers and may not be traceable. If the carb fits, wear it. Users have been mixing and matching these carbs in many iterations, over and over, for many years and are rolling along. Gas mileage be damned. Who knows what you are buying on Ebay, Swap Meet or CL unless super educated.

Snowman: You should have enough info now to fix and play trucks. Just don't do the RTV thing. And check for "Captains Bars"

Thanks guys. Very informative!

Bartamos- I checked and NO captains bars. I’ll get another carb gasket that fits.

Tclederman- The carb has a place for a center post; it’s not the one that has the air cleaner clamped around the throat. Does that mean it’s a later carb?

Again, thanks for your patience. I know I have a lot of questions and you guys have helped.

Yes, Snowman51,

It is a later carburetor, and it will use the later-style-attachment air cleaner.

Keep asking questions. Be as clear and complete as possible, and post images, if possible.

47-59 235 carburetor
60-62 235 carburetor