The Stovebolt Site Forums The Shop Area Engine Shop Replacement carb for 1966 327

Hey everyone...

I have a 1966 Chevy c30 with a stock 327 with a Rochester 4 Jet Carburetor. The engine only has 34,000 miles on it and it runs like a champ when the temp outside is good because the manual choke mechanism has broken thus making a rebuild kit useless and ever since I have had this truck, the carb is the one thing that has always given me troubles.. I was thinking of replacing the intake and carb altogether to get a little better performance out of her, but my son is against opening the engine up since it has not been touch (beside normal maintenance) it's whole life.

Does anyone know of a reliable replacement carb that can be installed maybe with an adapter? I am not interested in automatic chokes, kinda like the originality of a manual choke. I know I will be restricted in performance with the stock intake, but without a choke, it will be hard to start and run the truck in the colder months.

Thanks, Russ

Probably more work than you want but for performance and reliability put a FiTech, Holley Sniper or other fuel injection system on it. Set it forget it, no cold start problems, just start and go. Other opinions to follow.

It may be just as easy to find another Rochester to rebuild or at least rob the choke parts off of. I have an old one laying around from a a 68' 327, it has an automatic choke though.

The Rochester 4 jet is a square bore if I remember right, I don't know the bolt pattern but I would think the most direct fit on that manifold would be a Holley square bore, many available with manual choke. Check with Summit or Jegs for an adapter if needed. My preference would be a stock spread bore GM manifold and a Q-Jet.

I don't think I've ever seen a Rochester 4 barrel with a manual choke, and I grew up in the 1950's around a shop in Nashville that specialized in carburetor work. You might have some sort of Mickey Mouse conversion unit that was popular with people who didn't understand that automatic chokes are smarter than all drivers and most mechanics. Ditto for automatic transmissions!
Jerry

Rochester 4G has manual choke. https://hotrodcarbs.com/store/rochester-4gc-chevrolet-versions.html

Hmmmm- - - - -I stand corrected! That was definitely a limited production option, apparently only used on trucks. If a manual choke is some sort of a deal-breaker for some unknown reason, why not buy a 4GC and convert it to manual choke? Those kits are still available for folks who don't know any better.
Jerry

Jon H's website says 7027125.
1966 Chevrolet truck 327
Here are pictures of one that sold on ebay for less than $70.
It looks like manual choke parts are in place.
The casting looks like it is automatic choke capable.

Maybe the original manual choke parts can be repaired? Pictures?

Bornco,

Can you post pictures of what is broken on your carb? May help in deciding if repairable or requires replacement.

On another note (similar to "bouymaker"), do a search on ebay for "1966 Rochester 4 jet carb".

Right now, there are at least 2 4GC carbs with manual choke listed for sale (1 for $100 which pictures show exact match for "7027125" and another for $75 listed for parts only but picture shows manual choke setup).

Hope this may be of some help.

Dan

I have a 1966 Chevy c30 with a stock 327 with a Rochester 4 Jet Carburetor.The engine only has 34,000 miles on it and it runs like a champ when the temp outside is good because the manual choke mechanism has broken thus making a rebuild kit useless and ever since I have had this truck, the carb is the one thing that has always given me troubles.

I was thinking of replacing the intake and carb altogether to get a little better performance out of her.
But my son is against opening the engine up since it has not been touch beside normal maintenance it's whole life.


GEOLYTICS INC.

Thank you everyone for your response! The original carb has two issues:

1. There is an issue with the swivel point where the choke cable connects to it as if the linkage is too loose and cannot be tighten (Orange Arrow in 1st pic) If you look at the 2nd pic, you can see how the swivel is cockeyed (Leaning in towards the carb and is loose. You can see how it also cannot be adjusted with a screw like the swivel below.

2. The swivel section below that is also messed up and too loose. It is connected to the above and involves the idle screw that rests against it (White Arrow). The only way I can get the truck to idle is to put a washer on the shaft (White Arrow) to tighten up the swivel part so that the idle screw comes into contact and rests against it. If I leave it where the choke shaft can move freely (White Arrow), then it is too loose and I lose the idle screw capability. So if I want the truck to idle, I have to tighten the screw and lose the ability to swivel for the choke. The washer I placed there only tightens up the swivel choke part the idle screw rests against (So when you pull on the choke, it also increases the idle here), but the rest of the shaft can rotate freely.

See attached Pics... One from this post and the other of the choke swivel

That's an easy fix for any competent machinist. I'll be happy to make the parts you need if you're willing to send me the carburetor for a short time so the new parts can be fitted properly.
Jerry

Jerry that upper part (orange arrow) is staked. That may not be and easy job.
The lower parts (cam, linkage and lever) need to be removed and inspected for wear.

I have new (that I bought directly from Rochester) 4-Jet carbs with manual choke that were designed for Palmer Marine 355 CID engines.

Been selling them to the "cheaters" with 350's for years (hey kid, its just a 283, look at the old style carburetor, lets see how they run! ).

Jon

In '87 when grandma gave me the 3/4 ton c20 that grandpa had got ready for me before he passed, I was told it had a 283. Back then I didn't know about casting numbers or how to know what was what. I just ran it and kept it tuned up with parts that were for a 283. But it had the 4g on it. It may have been a 327, I don't know, but I do know that truck ran really good. That was when the speed limits got raised from 55 to 60, so people drove even more over the speed limit than before. I had to run the truck with the engine turning 4,000 rpm's just to keep up with highway traffic.

Just an update on this issue...

As it turns out, the choke bar had a round spring like clip that was pushed out of place causing the linkage to become crooked and jam. This threw off the lower linkage that adjusts/sets the idle thus causing the idle screw to jam to the side of the plate. To temporary fix that, I placed a washer to straighten up the linkage so the idle would work (As seen in the pic - yellow arrow shows the washer and the blue shows the idle point), but this would not work in the winter when I need the choke. On top of all this, the carb developed a gas leak from sitting.

So, the whole problem was the truck was sitting for a while, someone pulled real hard on the choke to try and start the truck, and the rest is history.

In the mean time, the gas leak forced me to look for a rebuild kit (not as easy as I thought, but I found one so I bought two as a backup). I broke the carb down, soaked the carb in carb cleaner and started the rebuild. This is when I found the round ring for the choke was not where it was suppose to be, which I fixed. The kit came with a tension spring that straighten the lower assemble (thus removing the need for the washer as a temp fix), still had to bend the assembly back a little to get it to line-up. I discovered the gas leak was the brass fitting the gas line connect to (looks like it stripped the carb, but I took the washer out and grabbed enough threads for now, so it seals...), lubed everything up and now its running like a charm. I plan to look for a parts carb at Fall Carlisle. Thanks everyone for their input and help!

...Russ

Bornco,

Thats fantastic news that you were able to solve your carb issues.

Thanks for the update!

Good news on the temporary fix. I'd be all over Jon's new carb like white on rice, especially if you plan on keeping the truck for a while. A new in the box carb is a much better option than somebody's 60 year old "repairable core", especially one that's a bolt-on swap with no modifications. The next best option would be an intake and carb swap for a Quadrajet, one that's calibrated for a late-1960's or early 70's 327.
Jerry