Edelbrock Carburetor Information for your Imperial

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Tips from Jack (440):

Just checking in after driving my '73 with the Edelbrock 1406 for a week. This car has never run so well, (even when new) I took a 300 mile drive on Thanksgiving, and with a mix of city and highway (80mph) driving, I got 13 mpg. around town, where it would take 1/4 a tank to do one roundtrip to work and back, it's more like 1/16.

I now have a smooth and very quiet idle, and at wot, it really opens up and screams.

The TQ that was on the car was in pretty bad shape, and my attempt to rebuild it revealed some bad patch work in the plastic body.
(I must have been getting 3-4 mpg in the city, might as well just dump the gas on the street)

I'm still getting the choke dialed in, but all in all, I am very very happy with this.

I'd highly recommend this swap if you're having unresolvable trouble with your TQ.

Reply from Rich:

My '73 has the TQ carb, and after I had it professionally rebuild I get 11-12 mpg in city type driving, and 13-15 on the highway doing 65-70 mph. I thought about getting the Edelbrock, but I heard they were over rated. After reading about your success I guess it's a good investment after all.

Question from Charles (413):

I am putting a Edelbrock Performer carburetor with matching intake on a '62. Can someone hold my hand here, I had car apart a long time and would have a hard time if all the hook ups were the same as original. Where do I need to plug or splice a vacuum line? What about the linkage? 


From Rodger:

I don't remember if that intake manifold is the open chamber or a dual plane. If it is a open chamber intake you will find that your car will never perform as good as with any of the factory cast iron intakes. If the carburetor that you want to install is over 750 cfm's you will lose performance. Take note that I spoke of the car's performance, not the engine's (abilities). There are only a couple of after-market intakes that will out street perform the factories cast iron intake that was on any '68 and better 440.

On the back of the intake manifold is a spot for you to connect the vacuum plug so that you can run the large hose to the brakes and the small hose to the vacuum reserve canister. On the front base of the carburetor is a port to go to the distributor.

From Brad:

I am pretty sure the performer is a dual plane. With no other modifications, I doubt it will have any significant performance benefits, but I also doubt it will reduce low end torque. Let us know when you are done.

From Carl:

I don't know if it's of any help, but on my 440 in the 300, I have a Performer intake, in the picture section of my "new" 300 are some detailed pictures of the linkage and such. It might help.  http://www.robdiesel.com

Question from Adam (440):

I am replacing the carburator on my 1968 Crown Coupe with a new Edelbrock Performer series carb. I have the carberator, the throttle cable and linkage cable parts.

I don't want to get into the project and have to run back and forth to the speed shop. Am I missing anything? Spacers? Fuel lines? Any help would be great on this.


From Mike:

Not hard...I recently replaced my Holley 4160 with the Carter AFB..similar swap, I imagine. The edelbrock performer requires a fuel hose be spliced into your existing fuel line. Your current carburetor probably uses a screw in fitting. You will need about 2 or 3 feet of 3/8" fuel hose, and two screw clamps for the ends, to connect the existing fuel line to the carb. Make sure you put a fuel filter in the line!

You also need the Mopar automatic transmission kickdown linkage adaptor, from Edelbrock.

Other than that, the carb will bolt onto the existing studs, the throttle cable will attach right on...you may need to plug some of the vacuum connections to the carb with little rubber stoppers, if they won't be powering anything. You will have two ports on the front of the carb for distributor vacuum advance...plug one, use the other. One is a timed advance, the other is a full advance. I find my '67 runs better off the timed advance, but its a bit of a trial and error thing.

From Dick:

To add a little to Mike's excellent reply, the two vacuum fittings mentioned are "ported vacuum" and manifold vacuum. The proper one for the distributor vacuum advance is the ported vacuum, the other must be capped if it is not in use.

Ported vacuum can be identified by the characteristic that there is no vacuum present at idle, vacuum appears only when the throttle is partly opened, in other words when you are stepping on the gas a bit. This is because the distributor is not designed to provide vacuum operated spark advance except during acceleration.

Of course if these two ports are exchanged, the initial timing can be adjusted back to specification at idle, but if this is done, the car's performance will be quite poor, as advancing the throttle will reduce the vacuum advance, not increase it. Off idle performance will be noticeably reduced.

Follow-up question from Adam:

Thanks for the carb help... I got the Carb installed and it starts up great.. only problem is linkage!

Any help with the linkage conversion?

I was told by Edlebrock I needed a certain linkage conversion kit, which I got, but it does not seem to fit. Can someone give me some guidance on this one.

Seems easy enough.. but the converter does not seem to line up correctly.

Reply from Mike:

As I recall on mine, I think I may have had to drill out one of the holes. The bracket bolts on (with a bolt, nut, and washer) to the existing lever on the carburetor, but uses some of the hardware off of the Holley.

On a related note, did you get the electric choke hooked up properly? They can be a little tricky, but as long as the heater comes on when the key is in the "on" position and it pulls off fully when warm, you're "in like flint".

Reply from Dave:

That is a problem with those "adapters". They just are not quite right. The biggest problem is that the "ratio" for the trans kickdown lever is all wrong. If you can look at an original Chrysler carburetor, and check the distance from the actual throttle shaft to where the "slider" thing on the kickdown linkage hooks up, - you can see that it's wrong. I usually drill another hole in the correct spot, and "rig" it from there. The location is important, - you risk transmission damage if it's wrong.

Question from Adam (440):

I recently installed a new edelbrock performer in my vehicle, the car seems to idle fine but I cannot seem to get the thing adjusted corrrectly. The vehicle keeps backfiring, not sure if this is another issue all together.

Does anyone know an easy step to tuning in a carburator like this, I'm kind of going trial and error. Any ideas on this at all would be great.. thanks for any help..


From Dave:

Just dropped an Edelbrock performer 1407 on mine last weekend. I'll have to do something about the lack of a choke, but my nephew made me a deal I couldn't refuse. I replaced a Holley 3667 with this, so I had to go to a hardware store and buy about 5 bucks worth of screw, nuts and washers along with 3' of fuel hose and clamps, but it works good. If it is backfiring, maybe it's an ignition problem. All I did to tweak was turn the 2 mixture screws about 3/4 of a turn out from bottomed out.

From Mike:

The settings for the carburettor and timing, etc, will vary based on dozens of factors from vehicle to vehicle. That said, it sounds like you may have an issue with improper timing, or a mixture issue. These are my guesses. What I would do, once you've eliminated any possible leaks (hoses, gaskets, etc) as sources of gremlins, set the carburator mixture screws at exactly 2 turns each out from just barely bottomed out. Don't turn the screws in tight, or you WILL damage the needle points. Start the car, and adjust the base idle (vacuum advance disconnected and the hose from the carburettor plugged), so the engine is idling at spec- check the FSM, I think its 600 RPM in nuetral.

Now we play chase the tail. You want to set the base timing to something around 5 to 10 degrees BTDC. If the engine is fairly fresh, no carbon buildup on the pistons, and you're running 92 octane or better (perhaps with some additive for lead or octane boost) then you can go closer to 10. If its an old engine, that's been idled alot (carbon buildup on the pistons) and you're a cheapo who uses 87 octane goat urine, set it closer to 5.

Once you've set the timing to something you like, reset the idle to 600 RPM. Now, play lean drop with the carburettor- turn each needle valve screw 1/4 turn out until the engine speed stops increasing the more you turn them out. Then, start turning them in 1/4 turn at a time until the engine speed starts decreasing when you turn them in. Now reset the idle speed to 600 RPM.

Having done all that, and reconnected the vacuum advance to the distributor, let the engine warm up to operating temperature- 160 to 195 degrees F, depending on your thermostat. Park the car on a nice open area, get in, hold the brake pedal firmly and give it some gas. DON'T do this for more than 5 seconds, or you could damage the transmission. Just listen for pinging while doing this. Also, don't spin the tires. Just load up the engine at a higher RPM and see if it pings. If it does, back off the timing. If not, you can up it a little and recheck. You want it as high (advanced) as possible without pinging under load.

Once you've set it here, do some test drives uphill in high gear at 30-50 mph using as much throttle as you can without it kicking down into 2nd. Again, check for pinging, and adjust accordingly.

The guess and check comes in when you re-adjust the timing, the engine may want a slightly different mixture, so you can get into a loop of adjusting mixture and timing back and forth. The law of diminishing return applies here, though.

Question from Chris (440):

I just got my 1406 and was wondering what tips you all might have on installing it. Any comment would be appreciated! This is one step closer for reliable cruising!!


From Mike:

Step 1: Remove Holley
Step 2: Set Edelbrock onto manifold
Step 3: attach fuel line using piece of 3/8" rubber tube from Pep Boys, an inline filter, and some fuel line clamps from "Help!"
Step 4: Drop kick Holley into nearest garbage receptacle, or list on ebay for $0.99.
Step 5: enjoy the smoother idle.

From John:

One thing to keep in mind is that the carb nipple requires 3/8 hose but the stock fuel line is 5/16. I have the Carter replacement for my 69 & am facing the same situation. Some have suggested giving the clamp a "couple extra turns" on the 5/16 end.

From Steve:

You can get the 5/16 line over the carb fitting pretty easily. Lubricate it a little and push it right on.

From Eric:

While the 5/16 will fit the 3/8 (with a little lubricant), I have seen brass reducers that allow connections of hoses with different IDs.

From William:

While you're down at the auto supply getting those fittings, also take the base gasket that was supplied with the carb. Ask them to find you an OEM spec thick insulator gasket that has the plastic inserts around the bolt holes. From my experience, the gaskets supplied with many of the replacement carbs are the thin, cardboard or rubber ones that not only can put the carb throttle plate too close to the floor of the plenum of the manifold but also are prone to not be very durable. I've had much better luck using the OEM spec thick insulator gaskets like the vehicles came with from the factory (with the plastic bolt hole inserts, the possibility of cracking the base plate from uneven torque is greatly diminished too!). I also like to put a thin layer of silicone sealer on the mounting area on the manifold that the gasket will touch--makes removal and related clean up much easier should the gasket ever have to be removed from the manifold!

Question from Chris (440):

I installed the new 1406 last weekend and I am having a high idle issue w/it (1500 rpm with or w/o chock on). I don't know much of anything about carburators ( I know enough on how they opperate...I just don't know where to start adjusting it).

The only thing I have done was adjust the timing. It was 20+ degrees advanced w/ the old carb; but, is now set at 5 degrees. Is 5 right or should it be 7??? The car is a '70 Imperial LeBaron (440) w/ an automatic of course. I'm really not wanting to mess w/ something I don't know about. So please, whoever has adjusted this carb before please help me out.

I'd like it idling better before I take it too the muffler shop to have a muffler and rear pipe installed. Pressently it is running no exaust 3 feet behind the Y pipe due to me blowing it (the muffler) up back in December.


From Ken:

The screw on the left where the linkage attaches is idle screw.The two skrews in front are fuel air mixture skrews. The accellerator pump is on the left top of carb. Set timing 10 degrees before top dead center, TDC is zero.Car should run faster, turn left front skrew to left till it runs ruff,then turn it back till smooth. Do the same with right screw. Then the idle screw, turn it out till idle is at 850 rpms or to desired speed, this is it. Sometimes you may have to ajust the accelerator pump, just give it the longest through. This should get you what you want. The factory timing is top dead center on 1970 440's; today's gas is different then 1970's, so keep timing retarded to make up for the difference. Have fun with it, thatís how I learned, besides thatís what Mopars are all about.

From Joachim:

According to my MOTOR MANUAL the specs are as follows:

STD engine 5 degree BTDC 650 RPM in neutral

HIGH PRFORMANCE engine 2 1/2 degree BTDC 800 RPM in neutral for BOTH engines VACUUM hose must be disconected at distributor Points gap 0.019

Question from Dan (440):

I'd like to know if anyone has experience with replacing their old carburetor with a new Edelbrock? 

I can either take my old one to a mechanic to be rebuilt and hope to get it adjusted correctly myself, as I can not drive my car to the mechanic, or install a new Edelbrock 600 and not worry about it. NAPA sells the electric choke version for $249.00 and I understand it comes pre-adjusted for this engine. I'd rather spend the few extra bucks for the new carburetor vs. the rebuild and not have to mess with it. A friend suggested this, saying he did it on a Chrysler some years back and it worked great! But, before going this route I wanted to check with our club mechanics familiar with the 440 who might be able to confirm or caution against this.


From Rob:

I have a new Carter AFB 625 cfm. Only catch is, it's on a 360. They are basically the same carb. I know many people with these carbs, the one thing is to check with somebody who knows about the jetting. There are slightly different model numbers that come with different jets. If you truly don't want to mess with it, you'll want to make sure you get the closest jets out of the box. I know mine runs a little rich, but on a 440 it might be perfect.

Follow-up from Dan:

I called NAPA about the jets as you mentioned. They told me they can get a close match from the model # of the old one.

From Roy:

It depends on what kind of carburetor your 67 has. If it has a Holly carburetor, then you would be better off replacing it with an Edelbrock. However, if your car already has a Carter carburetor (The Edelbrock is a copy of a Carter AFB), you should look into getting it rebuilt. Also, if you replace a Carter AFB with an Edelbrock, you will need to get the lower portion of the air cleaner from a car that has a Holley or a later model that has a Carter AVS carburetor, because the throat of a 67 vintage Carter AFB is smaller than the Edelbrock.

From Steve:

I like the Edelbrock carburetors. Pretty much drop them on and drive away. You will need the Chrysler kit to hook it up to the throttle linkage and trans linkage. Also need to run switched 12V to the choke and recreate the fuel line from the pump up to the carburetor. It isnít that hard to do, but will probably take you an afternoon.

This page last updated November 12, 2004.  Send us your feedback, and come join the Imperial Mailing List - Online Car Club