Replacement carbs for 331, 365

[Caddy Wizard]

Has anyone had any experience replacing the Carter 4bbl or Rochester 4bbl on a 52-58 Cad?  I am having trouble with my Rochester 4Jet on my 56 60S and am thinking of giving up on it.  I am considering using throttle body fuel injection (I did this on a 49 Cad and am comfortable with the job -- it will fit on the stock intake manifold) or a Edelbrock 1406 Performer 600cfm carb.  Has anyone used this carb on a 331 or a 365?  If so, how did it perform?


Here is what I dug up on what you would have to do to use the Edelbrock on a 331 or 365....

If you ever wanted to replace your factory carb with a (supposedly) better performing brand new carb, you might consider the Edelbrock.  A lot of folks do that.  The one for a 54-56 Cad would be the Edelbrock "Performer" 600cfm model, part number 1406 for about $300 (or 14064 if you want the fancy, shiny finish for about $400).  It comes with an electric choke (a real plus).  You would also want the insulating gasket/spacer part number 9266 for about $20 to protect the carb from suffering from "hot soak".  Here is a description from Edelbrock's website....

"Several characteristics make our carburetors outstanding street performers. The first one is that they use metering rods to transition between circuits. They are unaffected by engine backfires, which means that there are no power valves to blow out, and the rods can be changed in seconds without carburetor removal or fuel draining. Secondly, they have the unique ability to "hold a tune", so once they're tuned, they stay tuned. What this means to you is that compared to other carburetors, the performance remains consistent and the calibration stays unchanged. The lightweight all-aluminum body is compatible with gasohol and blended fuels, and features a two piece body that resists warping. They are available ball-burnished for a bright finish or with our exclusive EnduraShineâ,,¢ coating that provides the brilliance of a chrome or polished carb without the maintenance or the high price of traditional finishes. The simple tub-type bowls and rear-pivot floats all contribute to a carburetor that's reliable, user-friendly, and is easily tuneable for miles of trouble-free operation.
Available in two styles: Performer Series® and Thunder Series AVS®
Edelbrock carburetors bolt on and run right out of the box
Dependable street performance and smooth throttle response throughout the power band
Float levels are factory set; adjustments are rarely needed
Change jets, adjust floats & replace needles/seats without draining fuel or removing carb
Two-piece design means no gaskets below the fuel level for leak-free operation
Get performance you can count on from a name you can trust... Edelbrock!"


In order to mount the Edelbrock to the stock intake manifold, you would need an adapter from TransDapt or similar.  I don't have the part number for that at the moment.  It might take a little tinkering to hook up the linkage correctly.  I had to make a special little plate to mimic the linkage on the carb when I did the EFI on my last Cad -- it is not a difficult job.  You just need to make sure to have the TV rod swing in the same arc relative to the throttle shaft as in the original carb.


I think the air cleaner base on the Edelbrock is a different size than a stock Carter or Rochester.  The Edelbrock needs a 5-1/8" air cleaner opening, while I think the Rochester is 4 and something.  There is a company (Technostalgia) that makes a nice, full-sized replica of the Cad/Olds air cleaner to go on modern carbs, like the Edelbrock.  Here is a link to them.  The thing costs about $125.  http://www.cool-leds.com/catalog3a.pdf


So, if one switched to a new Edelbrock carb without the fancy finish, but with a new air cleaner, it would cost about $450-$500.  You'd get a modern carb, electric choke, new air cleaner (paper filter).  The cheapest I could do an EFI throttle body set up is about $1100.  I could have Daytona redo my Rochester for about $500.


Art Gardner

[Jay Friedman]

Art,

If you don't have your stock Rochester rebuilt, I would go with the Edelbrock carb.  It sounds like a win/win situation as it resolves many of the problems those early Rochester 4-barrels had and costs less than rebuilding a Rochester.  EFI, as you know from the '49 you so equipped, leads to more problems than it solves and only improves peformance marginally.  I would not spend the extra $100 on the fancy finish for the Edelbrock as these carbs only had a dull bare metal finish when new.  (I know this since I'm old enough to have worked on them back then.) 

Questions you didn't address re: the Edelbrock is how it deals with the gizmos on the Rochester which regulate the idle speed for the A/C etc. 

Jay

["Cadillac Kid" Greg Surfas 15364]

I hesitate to say it, but it seems that I am becoming a "purist".  Although this might be a super subject for the Modified Chapter's website, I can not think of why anyone would even consider the convoluted path of this modification on a stock car.  The Rochesters and Carters were tried and tested to provide smooth, efficient, powerful operation by GM, and have doen so for decades.  An aftermarket carb of any type was not designed specifically for your engine in your car, and as Jay hints at, does ont have the Idle speed-up and throttle linkage connections your car requires.  Again, this would be an interesting project, but if all you are after is a well running engine, I personally would (if I could not do it myself) find a reliable bebuilder for the stock carb.
Greg Surfas

[Caddy Wizard]

Thanks for the comment.  I am not trying to hop up the car or turn it into a Modified Cadillac.  I have just had bad experiences with the Carter and Rochester 4bbl carbs over the years.  I have previously owned a 56 Seville and a 55 Series 62 Sedan (drove that one as a daily driver for about 12 years).  Currently, I alternate between my 49 fastback and my 56 Fleetwood for daily transportation.  In fact, I don't have a "modern" car to drive at all, unless I borrow my wife's car.  Neither car could be considered a Modified Cadillac, I think.  Heck, the 49 is still 6v.

I have already carefully rebuilt the Rochester carb once.  I suspect that I overlooked some play in the throttle shafts (causing some small vacuum leaks around the shafts?).  I did have an issue with one of the floats not being set correctly (operator error!), but I fixed that recently.  I was a professional mechanic for 10 years and know my way around engines and carburetors reasonably well. 

My 56 Fleetwood's Rochester 4Jet performs, I think, about like many of them do.  As is typical, when you let the car sit for a few days much of the gas in the carb evaporates and then it takes a while to start.  The choke can be a little erratic.  Park the car in the garage with the engine hot and you'll get some fuel smell in the garage as the hot carb boils off some fuel (wife complains).  Idle is stable and relatively consistent, full throttle acceleration is pretty good, but there can be some hesitation at times transitioning from idle or near idle to speed.  Sometimes it will diesel on me if I shut the engine off hot (to minimize this, I try to remember to turn off the air conditioning before turning off the engine, so as to lower the idle speed before shutting down the engine).  The AC idle speed-up solenoid works perfectly.  The anti-stall dashpot on the firewall is a new one I picked up and it works well.  So far, this particular carb hasn't done the evil deed of leaving me stranded on the side of the road or in a parking lot (unforgivable in my book).  So far, no problems with vapor lock, even though this 365 runs quite warm compared to a 331 (but perhaps is running normally, or even a tad cooler than most other 365s).  Fuel economy is, of course, an oxymoron in this case.


I had similar problems with my 55 Sedan for years. On top of the above, at times it would leave me stranded.  Every so often I would drive the car in hot weather, pull into a business or a client's office, and when I would go to leave, the darned car wouldn't restart (gas had all boiled out).  I haven't had that problem as yet with the Fleetwood, but I have seen this happen to others as well.


I have rebuilt the Carter 722 in the 49 and it performs very, very well.  Idle can be a little inconsistent (some days it idles absolutely perfectly, other days it is only a good idle).  But overall, the 331 with the Carter 2bbl is just a great performer for me.  I wish my Fleetwood ran near as well as my 49 Fastback.  I just want the 56 to perform properly and based on my past experiences with mid-50s Cadillacs with this carb, I am sort of skeptical that one can ever make the darned thing perform as well as my 49.  So that has got me thinking about alternatives to continuing to mess with the Rochester.


Art

[cadillacman]

for what its worth, my 49 Cadillac has a Edelbrock fitted 600cfm and its easy to install and set up.
sorted alot of problems out for me and run's well now.

[Caddy Wizard]

Interestingly, the Edelbrock 600cfm carburetor is supposedly a Carter design manufactured for Edelbrock by Weber.  It even has metering rods like the 49's Carter 722 has for providing both power and economy, depending on conditions/demands.


Thanks for letting me know that the Edelbrock worked well on your 49 331.


Art

[Caddy Wizard]

One more thing to remember about these carbs is that they were designed and tested in the 50s.  Today's fuels almost all have alcohol in them, which makes the fuel more volatile.  So today's gasoline is much more prone to vapor lock, boil out, etc, than it was in the 50s.  You don't hear about those complaints much among modern cars because modern cars use fuel injection.  Fuel injection is a closed system, with no part of it being open to atmosphere.  So normally the fuel can't boil off or vapor lock in a fuel injection system.  And carbs that performed perfectly well in the 50s don't perform near as well today because of the difference in fuel.


On top of all of that, these 4bbl carbs were the best 4bbl carbs available at the time, but the 4bbl technology was pretty much brand new.  By contrast, the 2bbl Carter 722 was a highly refined product of years of incremental improvements.  Not surprisingly, the 4bbls of the early to mid 50s were not as highly developed (yet) as the previous 2bbls. 


Anyway, I am still hoping to hear from others about their experiences with the Edelbrock, which SUPPOSEDLY is superior, but people will say most anything to sell products....


Art Gardner

[Dave Shepherd]

The Carter AFB ( Edelbrock) can be just as subject to vapor lock with the aluminum body, if you do the conversion you will need an insulator between the carb and manifold, I have done quite a few 4 gc's and have not had any issues other than vapor lock, but for sure the E'brock is a simpler design all around and less troublesome. The fuel bleed down can be corrected, same type of issue the Quadrajet had.

[2danreed]

Thanks for all the good carb  info.   Art,  I have no experience swapping  carbs on my '56 sedan, but I have had good results rebuilding the original Rochester. I had to rebuild it back in the late 1990s and its been trouble free ever since. Your right on the money with how you get some fuel evaporation after sitting a while and the fuel smell after pulling into the garage with the engine hot.  The hard starting problem was solved by installing an electric fuel pump. I throw a switch under the dash to quickly get fuel up to the carb and I can get the 365 to turn over with the first turn of the key - I turn the electric pump off once it fires-up then operate from the stock fuel pump. Probably added a few years to the life of the starter.

Like I said, its been over ten years since I had to rebuild the Rochester, but I don't remember the rebuild kit being very expensive. One modification I made many years ago that made a world of difference was installing electronic ignition. That too has been trouble free since I installed it in 1999.  Also, just to add context - My '56 is a driver. Even over the winter. If the roads are dry I drive the car. Just wanted to let you know that any modifications, rebuilds, or replacement components have had plenty of miles of testing.

Dan 

[Caddy Wizard]

Here is another bit of grist for the mill.  I found a place that has a NEW Rochester for my car.  Supposedly a NOS carb that this carb shop got from GM and has gone through with a new kit.  Supposedly a direct fit for my car.  But they want $1600 plus 7% tax and my old carb (or else they'll charge me a $250 core charge).  Ouch!  Not sure $1700 to switch carburetors is a smart move on my part.  Wife would have a cow.


Car is running pretty poorly this week, adding to the angst.  I thought it was going to quit on me on the way back from lunch today...


Art Gardner

[slopez001]

hello folks, I'm new to this site. i have a 56 series 62 with carb problems. i was also thinking of replacing the carter with the 1406 edelbrock only because i have one laying around and i don't want to wait for kanter to ship one to me in 5 weeks. i cant rebuild mine cause the flange cracked in two spots. so does anyone have pics or instructions on how to install this edelbrock on my caddy

thanks

[55 ledsled]

Hello,
I have a 54 Cadillac motor with a Rochester carb on it.  It was rebuilt by a professional and continue to have issues like not wanting to start easily and dumping fuel into my oil. The other day I started hearing lots of lifter noise and found out the newly changed oil was pretty watered down with gas. I am ready to junk the Roch and install an Edelbrock. My question is, you all say get the 1406, but Amazon says the 1406 is not correct for the 1954 and that I should get the 1400 which is more expensive. I believe you guys over Amazon but thought I would check. The only thing I can see is the difference for smog engines? Any input on this?

[fishnjim]

Sounds like a stuck float, bad needle, if pouring gas down the hole.   
Can be rebuilt.
For new, Call Edelbrock tech service.   800-416-8628
I had a 1405 Performer on the '58 when it came but there were other issues.  Still here as I got a correct afb for it.   Then went to 3x2.   I recall the even numbers are electric choke.   It's a Carter AFB in Edelbrock logo.   They bought the patents/business.
Those early '50 4bbls were a bit tricky and they changed them every year trying to perfect them.   Add about 60+ years of wear, aging, etc and miracle they work at all.   Motor conidtion has a lot to do with how well it'll run.

[J. Gomez]

Hello,
I have a 54 Cadillac motor with a Rochester carb on it.  It was rebuilt by a professional and continue to have issues like not wanting to start easily and dumping fuel into my oil. The other day I started hearing lots of lifter noise and found out the newly changed oil was pretty watered down with gas.

Hmmm ok let’s think this through; how can a bad carburetor get fuel/gas into the oil. 

The only culprit in this case would be a bad fuel pump diaphragm which would leak fuel/gas into the oil filler tube. This particular fuel pump problem is a well know issue with several '5X folks here.

Before you can take the road in changing the carburetor I would suggest checking the fuel pump first since it may seem you have a faulty one.

Maybe start a new fresh thread since this one is about 9 years old.    

[55 ledsled]

Ok thanks. It always started hard even while futzing with the choke. I also believe that the fuel is being boiled out after I shut it down. It is a new fuel pump and I suspect that the fuel in the oil is from pumping of the gas pedal to get it started from a cold start. I just put electronic ignition in it and re-timed it. It also is a bit retarded on the timing but runs much better. Once I get it started it seems to run OK and will re-start no problem after its warm. There also seems to be a slight miss that is hard to detect unless you listen. I changed the plugs out as well. Plugs looked good other than a slight white tint but not bad.

[64\/54Cadillacking]

Hello Art,

I recently acquired a 54 Fleetwood that has been somewhat “altered” but not in a good way.

When I got the car the first thing I told myself was that it needs the original carburetor.
So I searched Ebay and found a Carter WCFB hearing that the Rochesters were problematic of this vintage.

After cleaning up the Edelbrock 1406 carb and reinstalling it back on the car, the engine ran a little better, but every time I would put the car into drive the engine would shake and stall on me. So it got me thinking something else is wrong that I possibly overlooked.

I didn’t realize how small the intake ports are on the 331. The Edelbrock has larger throttle plates and is a much larger carburetor compared to the Carter WCFB. The Edelbrock doesn’t match the size of the smaller ports of the 331 which can cause inconsistent fuel combustion.

What made matters worse was that the adapter plate on my 54 was too tall so the Edelbrock sat higher off the intake manifold causing a vacuum leak and too much space from the throttle plates to the intake ports that there wasn’t much fuel getting into the intake for a complete burn.

The Carter on the other hand matches perfectly and sits on top of the intake like it’s supposed too.

I can’t say if the Carter will make my 54 run better since i am waiting for a part for it in the mail. But I can give you an update on how the original carb performs and my progress once I get the Caddy up and running again

[fishnjim]

"King";
Be careful, that "adapter plate" might be required.   It's probably an insulator to prevent/direct conduction of manifold heat to carb.   Vacuum leak/condition is another issue.

The ratio of fuel/air is more important than volume.   It'll only pull the amount the vacuum can through the venturi.   Carb CFM does not have to match exactly, it just what it's capable of WOT.   I suspect there's another gremlin in your motor.   But hope your carb swop cures it but will need to be adjusted and tuned properly also.   That's a little more tricky on the old ones.

[V63]

I put TB FI on a 1957, and remain extremely pleased. In fact, I have little desire to deal with  any carburetor issues going forward. Convert all of them for dependability And by default ... safety ! Enjoyability!

Yes, as engineered they were wonderful at the time. How have driving conditions changed?  street lights?  speed limits? traffic congestion ? ... oh  and mandated alcohol fuel? Moreover,  Global warming 🤦‍♂️.

You have empathy and blessing with your decision of FI conversion!