The Stovebolt Site Forums The Shop Area Engine Shop Gm 261 carburetor help

Hey there,


I'm putting a 261 together and need a carburetor for it. I've read that the 261 carburetor is slightly bigger than a 235 carburetor. All of the reman units i find listed for sale are for 235/261. So my question is would a reman for a 292 be a better option and will it bolt up to the 261?

Thank you!

The only carburetor I'm aware of that was specifically designed for a 261 was a Rochester B with a slightly oversized venturi to accommodate the extra displacement. Those carbs are scarce, and they have a host of design problems that haven't gotten any better with age. Try to find a Carter YF calibrated for an AMC/Jeep 258 cubic inch six. It will have the same manifold stud spacing as the Rochester, and it's a much better design. The 292 carb would run pretty lean without some major rejetting.
Jerry

I ran a "B" from a '67 292 on my 261 for awhile, as HRL states, I had to dink with bigger jet but it ran pretty well.
I would agree, find a Carter YF calibrated for an AMC/Jeep 258 cubic inch six.

I have 2 Rochester Bs made for a 261 and both have warping issues that cause internal and external fuel leaks. Also, there is some wear in the accelerator piston bore. I am one of those who is not fond of the B, so I decided to use something else. Heads-up info:

In 1960, the design of the Rochester B changed to a different mechanical connection for the air cleaner. The Carter YF for Chevrolet changed as well. This is just one of the "gotchas" that you can run into when looking for a different carburetor for a 261. You also can have throttle linkage issues such as type of bell cam, on the engine. Then there is a difference with the Carter YF models (Chevrolet, GMC, Ford, Jeep etc.) where throttle arm up = throttle valve open versus throttle arm up = throttle valve closed. Then another carburetor issue of ported versus non-ported vacuum connections for the distributor timing advance. Then some of us prefer a manual choke carburetor for our "Stovebolt" engines. It's not fun to spend $$$ on a rebuilt carburetor only to run into the adaption problems. Homework is required. If you are rebuilding your 261 then you need a known good working carburetor before attempting the engine break-in run.

I have a Carter YF 2100 on my 261 in my 55 1st. Cold cranking is excellent even after a month of sitting. The only issue is that it was designed for a 235 engine, and you lose a little bit of power going uphill full throttle.