The Stovebolt Site Forums The Shop Area Engine Shop Best Carburator for 235 6

I am just not happy with my Rochester B carb. They are not awful, but just not happy with performance. What is the best 1 barrel in your opinion and why?

Thanks,

Mike

Although I have Rochester on my 235, I hear that Carters run great on these Stovebolts. So, I'm rebuilding a 3211s and a 2100s. The first one has an auto choke and I'm not sure if I'm going to plumb for it yet.

Carter designed the YF specifically for the Chevrolet inline six and intended it to be a bolt-on replacement for the Rochester B. They sold over 1,000,000 of them to Chevy owners back when the vehicles were still new.

My truck also has a Carter YF. I've put over 10,000 miles on it since I rebuilt it.

Rochesters have problems with warped castings causing various problems.

Search this site for many threads about the pros and cons of Rochesters and Carters.

Thanks for the info John.

Does anyone you know of have anycores for sale to rebuild ? manual or auto choke.

Mike

They turn up on ebay now and again.

Before buying one, contact Jon Hardgrove at The Carburetor Shop (573-392-7378) or send him a PM on this forum (goes by the handle carbking).

He'll tell you the exact Carter Carb to look for. There are dozens of different ones that are all similar but with different specifications for different makes and models.

I had a FrankenCarter on my truck. It was cobbled together from a couple different Willys carburetors. Jon helped me with obtaining a correct carb for my engine and a rebuild kit to go with it.

Truck runs and drives with no carburetor problems 4 years later.

Mike - Put an ad up in our Truck Parts Wanted forum when you figure out which one(s) you want to pursue.

Thank you Dan

Mike shoot me a PM. I have a couple of YF's.

Mike - see this tech tip for Carter YF model numbers designed for the Chevy 235.

https://www.stovebolt.com/ubbthread...tor-identification-carter-yf#Post1531510

Several different 235-specific model numbers, with some subtle calibration differences through the years. I suspect ANY of them would work just fine. I can personally attest that the 2100s works great for me.

If TUTS59 doesn’t have what you need, feel free to free to PM me as well. I have a YF core I’d consider selling.

I've run two Zenith 228s for a couple decades now. The ones I have came on GMCs but I don't know what size engine mine came off. They have adjustable main jets, which can be too much of a good thing. There is a temptation to lean it out "Just a little" in hopes of bumping the gas mileage. These main jets were optional to compensate for trucks running over a wide range of altitudes. Lean it out when you get to the Colorado Rockies or when you leave Ogden UT for a trip to Denver. But DON'T forget to turn the jet back out again when you get to the California desert. I did exactly that and burnt a piston.

All this said, I had a Carter YF at one time and the truck ran beautifully and got reasonable gas mileage for such a truck. After I put one of the two Zeniths I bought for a song on my pickup, I "lent" the YF to my GF when her 56 needed a carb but I never got it back before she sold the truck.

I had a YF on my 50 Stude Champion whose 170" flathead six delivered 28 MPG on the road consistently. While working on the YF, I substituted one of the Zeniths and both power and mileage dropped a lot but it ran smoothly. I surmise it was too big a carb for the little 170. I was glad to have the YF back in service when I finished overhauling it. It had an automatic choke that I liked and worked well. The Studie was a nice car, quality wise right up there with the top of the line GMs. I'd still have it but for rust I couldn't deal with.

Even though my Rochester has been working pretty darn well, I wouldn't mind getting a Carter for a backup or replacement. Running a '62 235 motor, is the YF 2100 series, the one to seek? I would also want a manual choke.

Craig, yes that was the last manual choke model made for the 235 but in 1959 Chevrolet changed the camshaft in the 235 and Carter suggested using the 3211S (the body/air horn of which was designed differently and which has auto-choke). The 3211 was the last carburetor Carter designed for the 235. I have one and like it a lot. Good luck!

What happened in 59 to the camshaft or anything else to the 235?

The main change I know of is they lowered the lift and changed the duration to get more torque at lower rpms. A no-longer available letter to dealers and service managers that used to be on their Heritage pages explained the design change and said it was done to help reduce smog in bumper-to-bumper traffic (I suspect mostly for LA and NYC). Some time ago I printed a copy of it but the last time I looked couldn't find where I put it and as I said after the pages were changed it along with some other stuff disappeared. As I recall they said they made the changes to improve fuel mixing and combustion at lower rpms. What I have here shows in 1958 the lift (for solids) was intake .4050 and exhaust .4141. In 1959 for solids was .3105 intake and .3325 exhaust. I think the change in torque and rpm was more pronounced with hydraulic lifters (which by then were all you got in passenger cars). Makes sense to me as passenger cars probably would have contributed to the smog problem more.

Parts of this make sense to me when I look at the Carter YF3211S and it might answer why Carter never redesigned the YF for the 235 after 1957. It has a 2 stage rod and the same size main jet as the YF2100s. However the economy size of the rod is .004 larger than the 2100 (meaning it will run leaner) and the power size of the rod is .002 smaller (meaning it will run richer). If the changes to the camshaft produced more power at lower rpms (which happened) it seems they'd cause the 235 to make less power at higher rpms and maybe the idea was to have it run richer in the power setting to offset that. Just guessing on that but the camshaft did change.

As long as we are nerding-out in Carter YF minutiae….

I have the opportunity to buy a YF 966S for not much money. I run a 2100s on my 1962 235 (in a 1951 truck) so I’m familiar with how it runs.

Referencing this page from Carbking’s site:
https://www.thecarburetorshop.com/CarterChevroletYF.htm

….and doing some “area of a circle minus area of a circle” math….i concluded the 966S is a slightly richer calibration than the 2100s.

Is it different enough that a guy is likely to notice?

Hard to say how much but I think you would notice. I owned one of these and used it on a 1956 235. I didn't like it that much and then left it in a box in the attic, forgot about it and years later tried it on the 1959 235. I didn't like it that much on the 1956 but I'd be hesitant to say if it was because it ran richer. After removing it I used a Rochester BC for a few years and that one ran very rich. This by the way was around 1974 and up to around 1983.

The 3211s is leaner than the 2100s and the 967s is richer than either of those plus the idle jet in the 967s is pretty good size. So there's that, but it the price is right it could be interesting.

Question: Can I use 235 carb and fuel pump on a 216?

Fuel pump: Probably, but you may need to replumb some fuel lines. Inlet/outlet orientation varies a lot on the pumps.

Carb: Can you? Yes. Should you? Probably not.

The mounting bolt spacing will be wrong and you’ll have to file or grind the throttle body to mount it up. It will also not be well-calibrated for your engine. The desirable versions of the 216 carbs tend to be more available and more affordable than the 235 ones. I’d recommend sourcing the right one.

Plus - the 235 carb will run lean on a 216 unless you do a recalibration.

Jon