The Stovebolt Site Forums The Shop Area Engine Shop What carburetor for '59 235?

I'm sure this has been covered to death, and I did search... Maybe my search skills are sub-par, but I was only finding old info (broken links, products out of stock, etc)
What is the best (performance, ease of install, ease of maintenance, availability) carburetor to replace my original Rochester B?
The truck is a 1959 Apache 31, with the 235.

Thanks in advance for your time and advise!

-Michael

A wise man once said, "ABC, Always Buy Carter".
Replacement Carter carburetors for Chevrolet (attached).
The cost effective ones (those you rebuild yourself) show up on ebay from time to time.
There's one now but you have to purchase the intake and exhaust manifold to get it.

YF 3211s is the only one listed as covering stock applications on a 1959 per carbking’s links.
The chart shown by bouymaker shows a couple of other options.

Forgot to mention, it depends on whether you want manual or automatic choke.
I have a note that the YF 3211S is a shorter carburetor for use on 1957-61 car 235 engines.
Apparently the car hood had a "lower profile".
Not a problem for 1959 trucks.


To recap: Determine the type choke and air cleaner you have to select the carburetor you need.

Carter listing published in 1959 listed the range for the 2100s/2101s as being 1953~1956.

I have often wondered why they could not be used on the later trucks.

I do not have a copy of the sales sheet posted.

Jon.

Jon I was scratching my head on that as well. Chevrolet used the Rochester B (not BC obviously) on trucks in 1959 (attached).

Brain spasm here:
I was thinking 1960 was the transition for truck to the low-profile Rochester B [my guess to have same carburetor as cars (standard transmission) for reduced inventory].
Chevrolet would have to use up their inventory of existing carburetors...1959?
1960-62 Carter decides to do the same but not make a low profile carburetor, like the YF 3211S, with manual choke.
That would allow Carter's existing inventory of YF 2100S to be used up.
Just a guess.

My '60 C10 235 has low profile / larger air horn diameter carb & air cleaner. Believe it was built that way. That's how it was when w got it in 1973.

I use the YF 3211s on my 1959 235. It starts easily, idles smoothly, performs well and runs lean enough. Just as there were differences between the 235s made in 1956 and 1959 there are differences between the 2100s/2101s and the 3211s. I don't know if it would be enough to make a big difference, but I do know the Carter engineers were a lot smarter than I am.

I agree with you Jon G. I'm just going by the Carter sheet I posted earlier.
It plainly says YF-2100S for 1950-59 Chevrolet trucks with 235 engine and manual choke.

Please correct me if I'm wrong. I don't mean this to sound critical. Just curious.
Your YF 3211S is installed on a 1959 truck with a 1959 235 truck engine?
You added a exhaust manifold choke stove and associated plumbing?
Did your air cleaner have to be modified or adapted to fit the YF 3211S?
I know this is a "sticky" topic but are you using ported or manifold vacuum for your distributor?

The 57 pass car had a lower profile hood. 56 and earlier used the Rochester carbs that did not have a cross bar for a stud because there was no hood clearance issue. So the air cleaners for those cars used a clam arrangement at the top of the carb neck to secure the air cleaner. for 57, the air cleaner changed to a slimmer top design and used the lower profile carb with the cross bar. The stud and wingnut arrangement was set into a depression in the air cleaner so the wing nut did not protrude above the top of the air cleaner. That is how they got it all to fit under the hood of a 57 chevy and later cars.

That being said, in 55, there were two types of 235 produced each using a different block. The lower powered mechanical lifter motors for the stick shift cars, and the higher power hydraulic lifter motors for the power glide equipped cars. So I would imagine there would be two carter YFs for 235s going back to 1950 when the power glide was introduced.

That distinction ended in 56 when all pass car 235 motors were made with hydraulic lifters. I dont know the answer to this one, but I assume that there were some trucks built post 56 with 235 motors and automatic transmissions, maybe not though, I dont actually know. I also assume that all stick shift truck motors were solid lifter motors. So I would imagine that there would be two different carter YFs for the later motors. The difference is likely in the idle circuits but that is just a SWAG.

Oh, I don't mind questions at all...yes, the engine is a 235 from a 1959 Chevy and the 3211s is installed on it. I used an air cleaner I picked up decades ago from a slant six. It had the center mount. At that time I was using a Rochester BC and that air cleaner fits both carburetors as both had the center mounting post and the slant six also used a one bbl with the same size bore. Plus it looks good and replacement elements are plentiful. About a year ago I bought 6 on Amazon for $5.25 each with free shipping. You know Carter dropped the manual choke with the 2100s. If manual choke is important to you, then the 2100s is one option...although I should be honest and tell you there are converters which allow you to alter an auto choke to a manual choke. Dorman makes one. I've seen people use these since the mid 60s, but I should further be honest and tell you I got over wanting anything with a manual choke around 1965. That is when it dawned on me the auto choke in good nick is smarter than I am at the same job. I didn't have to do anything with the exhaust manifold. The Carter bolts right on to the stock intake manifold. The exhaust gas flapper did need a new spring about 2 or 3 years ago, however. The Carter 3211s was designed for ported vacuum. Somewhere I have the specs for the slot if you need them. Since I only had the choke stove designed for the Rochester, I had to lengthen the tube connecting it to the carburetor, but about a year ago I found a stove designed for the Carter auto-choke models and will swap them sometime. Hope this is helpful.

Oh one other thing I forgot to mention...I did have to drill a hole in the bottom of the air cleaner to pipe a nipple for the suction tube for the PCV I added. (so it would draw clean air back into the engine).

Thanks for all the input guys!

Jon G, thanks for the info.

I finally found it....the 1960 Rochester B, BC design changes (attached).
Low profile carburetor design used on trucks beginning in 1960.

Before I "bug out" I wanted to mention this for reference.
Because of the change to a wider (2-5/8") throat diameter (air cleaner mount), the 60's Rochester B requires adapter ring(s) to allow mounting a 1959 and older original air cleaner (2-5/16").
I don't have a YF3211S to look at but I suspect the same adapter(s) would be needed here as well.

The 3211s (just like the Rochester BC with the lower body) used a 2 5/8" opening with a ledge for the cleaner to carburetor seal. So to use an older air cleaner you'd need to change things a bit...but you have room and it could be done.

I'm using a heavy 1955 3100 oil bath air cleaner for example.
It's a clamp type to fit over a 1955 Rochester B carburetor with 2-5/16" diameter throat that is maybe an inch or more high.
For the 1960 and newer Rochester B, you would need a reducer/spacer 2-5/8" to 2-5/16".
From the shoulder to the top of the adapter needs to be maybe 1" for the air cleaner clamp to work.
The low profile Rochester throat is only a 1/4" high (assuming same with Carter). Grub screws will not hold the spacer and air cleaner secure.
A rough idea is maybe use rivets or epoxy but that modifies the carburetor. Actually, I just now changed my mind on the adapters.
If it's not done properly, the air cleaner can fall off, hit the fan and punch a hole in the radiator or worse.

#1 YF-2100S for 1950-59 Chevrolet trucks with 235 engine and manual choke.
#2 YF-3211S for 1950-59 Chevrolet trucks with 235 engine with caveat to replace air cleaner to center bolt type. 1960-62 using existing air cleaner.

You could take the bracket off the carb that and use the existing screws along with a fabricated bracket to hold on that adapter for the oil bath filter

If we are going to talk design then I propose we open another discussion topic.
Then we could/should add the following:

1. It needs to fit both Rochester and Carter carburetors for the sake of being versatile.
2. It should work without modifying the carburetors and air cleaners.
3. It should be designed in a way that parts can't work loose and fall into the carburetor and damage the engine.
4. It needs to be cost effective (less expensive than buying a used center bolt air cleaner in a junk yard etc., for example).
5. The design does not cause an intake restriction and/or turbulence that would negatively affect air/fuel mixing.

Is there any way you could use a center screw with this air cleaner? If you are fortunate enough to find an older vehicle with a one-bbl air cleaner (low profile like was used in the 60s), you'll be in tall cotton.

J@@p Forum. Modified 1990 Caddy housing butted to a FLAPS filter.
We all have different tastes but it's not a solution I would want on my truck.

The type of air cleaner used on 1959 to probably 1965 Chevy engines is made as a repro item. About $150 with shipping as I recall, but has the center bolt, is lighter and looks right. As I recall, they're made for the 4bbl, so you'd need to get some 3/16" aluminum and cut yourself an adapter plate, but that shouldn't be difficult with a saber saw and a fine metal blade. Replacement elements ought to be available pretty easily also. Just another option.