Carbs for Chevy 250 3X1 manifold

I am collecting parts for a 51 Ford F1 ratrod truck. I have a 250 Chevy 6 for it and an Offy 3X1 manifold. Most of the engines I've seen have the old "potbelly" style B Rochesters on them. Will a newer 60s or 70s Rochester Monojet or single barrel Holleys or Carters work well with this engine and manifold? Will the Idle circuit have to be modified on the outboardcarbs? It will have a 272 duration cam with about .500" lift with home made headers using a header flange with single pipes from each exhaust port.

Any suggestions!

where did you get your intake im lookin for one or two twos or two ones just not a four bbl.

Sorry, I don't know anything about the newer carbs.
I have run 2 of the old Rochesters single barrels and currently run 3 old Stromberg BVOX singles on my old 6. '22

Boy, I don't know either. I've never played around with one of these engines, but they sure are cool dressed out.

Don

Check out this link

www.clifford performance.com

Several years ago I got to help a friend of mine put an "Offey" intake on a 77 Nova he had, 3 mono jets set up on a progressive linkage. It worked out real well.
Hope this helps

3X1 Manifold Carbs

I got the manifold from Speedway which, included the progressive linkage. Summit also has them. I talk to Tom Langdon at Stovebolt and he recommended the small bore B series Rochesters with the manual chokes if I want to use the supplied linkage. You will have to make modifications with any other carbs.. Carters or Holleys or new Rochesters. Which is OK....thats Hot Rodding isn't it. I've decided to use the Rochesters since I already have two that match need to find one more.

Sounds good.....

I would think you will need to lighten up the power valves if the carbs you use have them.

Weber ICH's or ICT's are what a bunch of the Ford 200/250 guys run nowadays. Holley 1904's or 1911's are a good size, but it is hard to find ones that are worth a crap. If you have the two matching carbs already, I'd use those, though.

If you are going to break in the engine, block off the end carb holes and run off of a known good center. You don't want to run into issues the first time you fire it up.

Only the center carb needs a choke AFAIK. Definitely use a progressive linkage, it will help with all-around economy and driveability.

I've got 2 Rochester 1 barrels on a home made manifold on a 250 six in my '35International. There is a post on it in the "Builds" section. I went to the Carb Shop for advice regarding jetting, etc. He suggested leaving everything stock and see how it runs. I made sure both carbs had the same main metering jet. The only adjustment needed was the idle mixture screws are out 3 turns instead of the normal 1 1/2 turns. The engine is stock internally and the carbs are on a straight linkage.

Here`s what I plan to run on my 194 chevy , offy intake w/3 stromberg 81`s

24dodge said:

Here`s what I plan to run on my 194 chevy , offy intake w/3 stromberg 81`s

Click to expand...

24, where'd you get the adapter flanges?

Larrowe & sons in Oregon , they are offenhauser pcs, Larrowe had the best price , lots of neat 6cyl parts there .....

Very Nice !!!

Nice looking setup there, 24.
What will you be running the 6 cyl. in? '22

the 34 International I picked up

dmw56 said:

I am collecting parts for a 51 Ford F1 ratrod truck. I have a 250 Chevy 6 for it and an Offy 3X1 manifold. Most of the engines I've seen have the old "potbelly" style B Rochesters on them. Will a newer 60s or 70s Rochester Monojet or single barrel Holleys or Carters work well with this engine and manifold? Will the Idle circuit have to be modified on the outboardcarbs? It will have a 272 duration cam with about .500" lift with home made headers using a header flange with single pipes from each exhaust port.

Any suggestions!

Click to expand...

Where might I find a header flange for a 230cid 6 cylinder?
Thanks

Ratcrazy said:

Where might I find a header flange for a 230cid 6 cylinder?
Thanks

Click to expand...

I bought an old set of headers and cut the pipes off. I've seen them in the past at Summit Racing for <$150. I've also seen them on Ebay or you can make them or have them made.

On Rochester carbs for a multi-carb set up the 2 outer carbs will need to be modified to work correctly. The idle circuit will have to be blocked off, the power valve removed and circuit blocked off. Make sure the throttle plates are completely closed at idle.

Any news on the Rochester Monojets working in the 3x1 setup? I am building a 3x1 for my Chevy 250, and looking for any info.
I tried three of the carbs originally on the truck (the medium sized monojets) with out modification and it was too much carb. I dropped down to the smaller monojet, and notice a big difference. Now I am modifying the outside carbs.
Should the power valve be removed and the passage blocked or left open?

I just joined, spent 5 minutes finding this discussion. I think I might like this place

Thanks

69chevytruck said:

Any news on the Rochester Monojets working in the 3x1 setup? I am building a 3x1 for my Chevy 250, and looking for any info.

Should the power valve be removed and the passage blocked or left open?

I just joined, spent 5 minutes finding this discussion. I think I might like this place

Thanks

Click to expand...

Yes remove and block the power valve. And welcome!

I use holley on barrels that came on the slant six. for headers i am making a set of lakester style. I got the flange off of egay for 36 bucks and i use a old drive shaft for the cones.