The Stovebolt Site Forums The Shop Area Engine Shop Carb for 261 Pontiac with 848 Head

What would be the proper Carb(s) for a 261 Pontiac with 848 Head?

Single carb or double, used or new?

Joerg - That depends on a few things. Basically it would have been a single barrel Rochester Model B (if manual choke) or BC (if automatic choke - more used on car engines than trucks).

The Chevy truck 261's used a larger version of the Rochester B than the 235 and even smaller 216 versions.

You can check out Rochester carb identification info in several "Tech Tips" found HERE.

There are alternative carbs from the Rochester, like the Carter YF series, which many folks prefer, but again you'll need to be sure you get one that at a minimum is for a 235 or 261 engine.

If you want simplified use/maintenance and tuning, stick with one single barrel carb. You can certainly go dual carbs, but that can become a real pain in the you know what to setup and balance.

On the used or new question, you will not likely find any "real" Rochester or Carter carbs, only used/rebuilt ones. The "new' stuff being offered looks pretty and close to accurate, but is all made overseas and more often than not is barely usable out of the box. They are known for very poor quality unfortunately.

Good morning Joerg - the 1961 (possibly later as well) Canadian Pontiac used a Carter type AS carburetor number 3114s.

The type AS was basically designed as a 60,000 mile "throw-away" unit; rebuilding one is a nightmare.

Regards.

Jon

Just from an engine displacement perspective, the Carter YF for an AMC/Jeep 258 cubic inch six looks like it would be a good choice. Fuel line routing and throttle linkage would probably need to be tweaked a little. Maybe Jon would be willing to weigh in on the feasibility of that idea?
Jerry

if i were to build a 261 for myself it would have a Clifford or 4 barrel intake with a 2 barrel adapter or a small 4 barrel carb, of course all jetted properly. i see them at swap meets in the 200 - 300 price range.

https://cliffordperformance.net/store/ols/products/42-4500wh-chevy-235-intake-manifold

A couple of gentlemen have offered suggestions.

I don't necessarily agree or disagree, as you have not really given us a reason behind the question.

BASED ON YOUR DESIRES FOR THE ENGINE, you have many options:

(1) The original Carter type AS 3114s. In my opinion, NOT a really good carb, but it was calibrated for the engine and everything fits. Should you choose this option, I would look for a new old stock unit. There is virtually zero market for any of the type AS. We have several new old stock, just none of this number. If you find a new old stock 3114s, I don't think you will find it to be gold plated

(2) Another single carburetor; Jerry's idea of a AMC/Jeep 258 Carter YF is a sound suggestion.

(3) You mentioned a double carb arrangement. I would suggest this may be the worst option, as the intake to head interface is not optimal for two carbs.

(4) If you want multiple carbs, then three is MUCH better than 2, because of the afore-mentioned intake to head interface. Three Willys Jeep type W-0 ID number 636s would be ideal.

(5) A Clifford intake with a two or small four barrel. Should you consider this option, carefully consider the definition of the word "small". Carter produced a couple of WCFB four barrels for Studebaker (2214s and 2219s) that flow just under 300 CFM, AND THAT IS OCEANS for the 261 for street use. Anything larger MIGHT run worse than the original unless the engine is highly modified. If you go with the two barrel, then the AMC Jeep 258 two barrels might be good options.

Remember that should you do anything other than original, possible modifications might include: intake, linkage, fuel lines, fuel delivery, air cleaner, and maybe relocating other engine accessories.

Should you wish a recommendation, please give us more information about the state of tune of your 261, and your plans for the build.

Jon