Installing Edelbrock 1406 carburetor to replace Carter--new carb leaks below the bowl! New gasket used.

Everything went quite well switching from Carter to Edelbrock, except for usual issues(no place to mount the transmission kickdown switch). Car runs and starts much better! BUT, it leaks on the choke side, tightened properly with a new gasket supplied by Edelbrock. I will try a new gasket, and reluctant to use "gasket sealer" with gasoline, though I might try it if I have to. There's no adapter between the carb and manifold. The manifold top was spotless, apparently recently machined as it had swirl marks, so the surfaces are pristine with no old gasket material. Don't want to return the carb but may have to.

ALSO...the new carb has a PCV hole in front, with no hose from my car to match(the old carb did not have this.)  Just plug that hole up? Otherwise, everything matched and I think the electric choke will be much better than the old style on the Carter.

THANKS to all the awesome people who comment with authority on this forum!

Preston Bealle

Darien, CT

1964 DeVille Convertible

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Check the float level on the new carb. It may be too high, causing the leak.  The original carb has a spacer with the PCV port, so you will run the original PCV hose to the new PCV p[ort on the edelbrock carb.

Thanks, Russ, will check the float. The original carb, the Carter, actually has a screw and spring where the PCV goes, there's no hose. So I'm thinking of taking the screw from the Carter and putting it in the Edelbrock. Smoke and vapor is coming out of that hole but I have nothing in the car to put there, unless I install a new hose that does not exist.

You have to remove the intake manifold and plug the old choke tube —for the old choke — on both ends 

or  hot exhaust gasses will be escaping into the engine bay to close to the carbs base 

I used all the stock Carter carb gaskets and the stock spacer under my Edelbrock 1406

you will need to plug —one of the two PVC inlets— you now have —at the base of the carb 

Plug them both if you have no PVC hose in that location ( a Cali car ? ) 

I DO NOT think the car will run correctly —without the stock spacer and stock gaskets under the Edelbrock 

The reason being the Edelbrock carb is almost an exact copy of the Stock Carter so why would you Not use the same set up under it 

The spacer keeps heat off the carb 

The gasket seguence is —regular gasket — phenolic spacer — regular gasket — aluminum gasket under base of carb — never used a sealer on any carb base myself — no problem 

My car was running lean with the new carb and —had to be rejected —two steps richer with the help of the Edelbrock techs

Plugs were burning whitish and got them to the correct — paper bag color 

The above is required for the job to be done correctly 

The carb should then be — Tuned once and only once - after a very complete tune up iis done on the engine to maximize engine performance and gas mileage 


That's great advice, at just the right time. I took the Edelbrock back off because of the gas leak on the choke side and I'm going to reassemble in the order you said(gasket then spacer, etc). I have to think some kind of gasket leak is at fault rather than the floats being set wrong on a brand new carbutetor. 

A leaking carb and hot exhaust gasses ---coming up your old choke tube now --is not a good combo
Pls get that tube blocked on both ends of the intake to use the Edelbrock carb with an electric choke


I don't think I HAVE a choke tube. There was not one connected to the Carter carb and the nipple where it would go is pinched shut. I do not see a tube on that side of the engine, nothing is connected, nothing is there. The car was very difficult to start(starved for gas and non-functioning choke) but ran well when warm. This Edelbrock changeover has a lot of variables. The new carb was installed in only about an hour but a lot of follow-up hours and it's still not usable because I can't identify the leak from underneath the carb. Many thanks for your help. Next step is try to add another gasket. Leak might be through the metal shim. Or, if I take out the spacer and the aluminum shim/gasket and reinstall and there's no leak, at least I've identified where it's coming from and can add them back in.

Edelbrock carbs are wonderful but sometimes need to be tweaked a bit to run on a Cadillac engine.  I have one on both my '64 coupe and '57 coupe but in both circumstances the main jets needed changed in order for the car to run just right.  

Remember, those carbs are geared towards Small Block Chevrolets which are in the same ballpark as our cars. Spacer is a must on this application. I have used this one with great success.  It negates the "heat soak" problem we have in Indiana with 10% ethanol infused gasoline PLUS it seals the base extremely well.  It may sound crazy but the lower castings on the Edelbrock are not always 100% straight and need a little help to fill the void. Keep plugging away with the carb, it is a great alternative to the original and will give you years of great service once you work out the bugs. 

Absolutely agree. You would never sit the carb straight onto the metal intake.  The original Bakelite intake manifold to carburetor insulator/spacer provided not only some insulation from the engine heat, but also raised the carb a bit providing better air/fuel mixing.  I use the Trans-Dapt TRD-2446 0.375 " (3/8") insulator spacer as indicated in my Carb Project write-up.

And I agree performance can often be tweaked by changing out the jets. You can get calibration kits from Edelbrock that has an assortment of metering rods, jets, and step-up springs.
The kit tailored for the Edelbrock 1406 600cfm carb is the 1487 kit.
The kit tailored for the Edelbrock 1411 750cfm carb is the 1489 kit.
Below is a picture of the 1489 kit which I used:

You do not need the metal shim. Since you are running an Edelbrock, the two exh ports under the carb need to be blocked off.  Tap and run a bolt down each hole and cut the head off.   Use the spacer with two gaskets and you should be good.

Tony is referring to the choke tube that runs through the intake manifold. There should be no exh gas comming gout of the holes.

You may want to read thru my Carb Project write-up.  There are several things to consider when installing a carb. From the factory a heat riser on the LH exhaust manifold is closed at cold crank up to force exhaust gases across the engine thru the center intake exhaust port to rapidly heat up the engine. Even with the heat riser open when engine is warm you still get 300+ degree temps across the center section of the intake from bypass gas (there is a video showing mine pegging about 305 degrees), so many including myself remove the heat riser (or butterfly) and block off the center port between the heads and intake (you will see pictures of how I blocked it on my write-up). You can also block the 4 exit points in the carb including the 2 at top of intake in the runner channel, and at both ends of the internal heat choke tube that runs from bottom left of intake to top right where the factory external choke would attach.  As long as your internal choke tube is intact and not cracked or broken, the exhaust gases cannot leak out from either end. Once the internal choke tube is compromised, you will have exhaust leaks unless you have blocked the cylinder head to intake ports as previously mentioned.
If you have an otherwise nice intake manifold, my suggestion at this point is to simply block at the head to intake port. These intakes are getting harder to come by, and if you ever wanted to go back factory you can reuse if you have not removed the choke tube and/or blocked the 4 exit points. My intake already had a rotted choke tube and thought blocking at the 2 top channel ports and 2 choke tube end points would be be all I would need, but again I was still getting 300+ degree readings and would sometimes try to vapor lock on super hot summer days sitting in traffic. Blocking that head to intake port and reducing the temp down to about 195 degrees... same as the rest of the intake... fixed that problem.

Great point Jason, I always forget about that silly heat riser since I changed my motor to a 472 and run custom dual exhaust.  The heat riser from my car is probably lying in a field somewhere in north central Indiana? 



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