Four barrel for 318?

I picked up a complete @ 85 360 4 Barrel, I plan to rebuild at a later time. Any problems with putting the intake and Quadrajet on my 78 318? Kick down is not a problem, mine is a 4 speed. I does, however, use an electric choke on the 4 barrel, and the 318 uses a thermostat in the manifold. Any non expensive suggestions would be appreciated.

That Q jet is a dog. They can be tricked to run well just like the TQ but it costs $@$500.00. Chrysler went from the TQ to the Q jet, not any better. Try an aftermarket carb. The smog motors suffered from all sorts of emission issues. The carbs were the last stop to get emissions down. They all ran like dogs.

A QJ can be made to work beautifully but it needs someone really good with them to get the right jets, metering rods, metering rod piston springs and hangers, etc.........A late buddy of mine (who died WAY too young) was a wizard with those things. Also depends on what model and year QJ.
If you go with the QJ, all the electric choke needs is a keyed power source that's powered when the key is in "run". which can be found in the engine compartment. IIRC, the circuits with key on power have a dark blue wire.

78VOLAREWAG said:

I picked up a complete @ 85 360 4 Barrel . . .

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If I understand what you said, was you purchased an ’85 360 cast iron intake and the QJet that came off that vehicle?
Did you also get the kickdown linkage/throttle cable from same vehicle?
Did it come from a M-body, a pickup or a van?


The ’84 and older 4-bbls were Carter Thermoquads – but Carter went out of business mid ’84. The ’85-89 Chrysler 4-bbls were all Rochester QuadraJet’s and all of them were computer controlled.

If you are planning on not adding a computer – then I would highly recommend not using that carburetor. It takes a LOT of work to get that erm, ____ of a carburetor to function to any performance satisfaction. The same can be said with the computer controlled TQ’s. Once you remove the computer controls, they are just so rich in performance robbing emissions – they just don’t function well.

The older TQ’s (’72-74’s) were Rockstar’s. Some ’75-76’s was good/some weren’t. Most all TQ’s made ’77-84 were not that good (needed work to perform).

Getting back to your QJet, I’m not an expert on them and have only worked on less than 10 of 'em so my knowledge is weak. If a person can get the QJet baseplate to work on an older GM QJet (older than mid ‘70’s) – then you might have a great carb. I don’t even know if the baseplate (with Chrysler linkage) will even fit other QJet’s.

Personally, I think you can spend less $ on getting a known good carburetor to begin with (just pick one) than what it will take to convert this one to work well. If you have a carburetor (or two) located – then post links here so we can give our opinions on it before paying for it.


The ’79-84 360 cast iron intake is just like the ’85-89 version except the divorced choke provision is not machined. A person can get it machined, if wanted – but as mentioned earlier it might be better off finding a carburetor with electric choke already attached to it.

Personally, if I had any say, I wouldn’t risk back problems installing a cast iron intake. The Edelbrock Performer 2176/3776 aluminum version is much lighter, flows better and will fit almost any 4-bbl carburetor you have. A person can even find good used versions on CL or on eBay at a decent price. I happen to have a ’86 360 pickup iron intake in my garage – but its not worth the $ to ship it anywhere.

Getting back to linkage. I asked if linkage is from a pickup or a van (if present). The vans and pickups use what I refer to 1-piece kickdown linkage, which for most people will not work on FMJ’s (it hits the firewall before achieving WOT (Wide Open Throttle)). Only a very few people have been able to get the 1-piece linkage to work (due to a combination of production tolerances being just right).
If you do not have the correct kickdown linkage – you might want to look into a cable system.
BudW

Thanks for the replies, I believe the engine came from a pick up. No need for kick down, my wagon has a 4speed. The 360 build will come after my 13 year old can pay for it. I just wanted to move a little more air through the 318, for now. I was mainly worried about the electric choke. There doesn't seem to be a lot of electronics on the carb, just idle solanoid.

BudW said:

The ’84 and older 4-bbls were Carter Thermoquads – but Carter went out of business mid ’84. The ’85-89 Chrysler 4-bbls were all Rochester QuadraJet’s and all of them were computer controlled.

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Many of the 85+ pickups and vans came with non-CCC Quadrajets. I've got two sitting on the shelf, one that I pulled from an untouched van in the yard a couple of months ago. Passenger cars all came with computer controlled carbs, but those cars are rare enough anyways.

The stock iron intake will outflow the Performer. The Performer has real restrictive ports. It isn't until you step up to a Weiand, LD340, or RPM that you outflow the stock 4bbl intake. The Performer was purposely cast with smaller than stock runners to boost low-RPM torque and Seat of the Pants feel for 318 smog hogs.

I'm a Mopar guy all the way so I love the Thermoquad and when tuned right it is a great carb. But I've had '88 and '89 Diplomat Police cars with Quadrajets and they ran very well, and had that really nice four barrel sound like the Thermoquad. I'd prefer a non-emissions Thermoquad over any.

I wouldn't bother if the 2bbl is running good and your intent is just to pull it all out anyhow. Without a cam and exhaust to take advantage of the additional air/fuel you're not gaining anything.

Is your question related to hooking up the electric choke? If you have lean burn or used to, there is an ign hot wire you can use to feed the electric choke. You would want that working, especially up there where you live but even here in the tropics I wouldn't be able to stand the cold start up without the electric choke. I would go through the carb and get it really clean and adjusted before you swap it. It won't exactly feel like you're being shot out of a cannon or anything but it may make you feel a bit cooler. Make sure you have an air cleaner that works with all of the fittings pointing in the right direction and stuff like that so the car isn't down for parts for weeks or months. Depending on what your donor parts came off, stuff may fit, but not exactly. The quadrajet actually fits that intake pretty well if it's the casting I think it is.

The choke in the intake should have a wire already that you can connect the quadrajet to. Or any keyed 12v source. I'm guessing this has been done or abandoned in the last 3 years tho.

78VOLAREWAG said:

I picked up a complete @ 85 360 4 Barrel, I plan to rebuild at a later time. Any problems with putting the intake and Quadrajet on my 78 318? Kick down is not a problem, mine is a 4 speed. I does, however, use an electric choke on the 4 barrel, and the 318 uses a thermostat in the manifold. Any non expensive suggestions would be appreciated.

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Go for it, I'm not sure how much power you will find but that carb makes beautiful music when you put your foot to it....

Duke5A said:

I wouldn't bother if the 2bbl is running good and your intent is just to pull it all out anyhow. Without a cam and exhaust to take advantage of the additional air/fuel you're not gaining anything.

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I agree with the above and

Oldiron440 said:

I'm not sure how much power you will find but that carb makes beautiful music when you put your foot to it....

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and this

LSM360 said:

and had that really nice four barrel sound like the Thermoquad. I'd prefer a non-emissions Thermoquad over any.

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The thing is this, until your current carb runs out of airflow, the 4bbl is no advantage, even if it opens right after idle. Because......... any carb only flows what the engine asks for. So in effect, if the tires don't spin, you may be waiting until around 3000 rpm, maybe even higher. With an A999 and 3.21s , that's gonna be maybe 25mph in First, and 50 or so in Second gear .
So while the TQ may be moaning it's heart out, until the engine starts pulling more air thru it than the current carb/intake allows, that moan is just a moan, lol.
If you already own it, and you have the ambition, install it; cuz with the right rear gears, you will get a lil power for passing on the hiway.

I removed cats and added four barrel to a civi '85 Dip 318-2. While it was no powerhouse of course, a factory iron 4 barrel intake and quadrajet from a police car made a noticeable difference around 40 to 45mph like something kicked it in the rear. It was not awesome night and day difference but it definitely improved acceleration.

Aspen500 said:

A QJ can be made to work beautifully

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I agree. I have a 88 D350 and it works just fine. When looking at low budget,use what ya got .

AJ/FormS said:

I agree with the above and

and this

The thing is this, until your current carb runs out of airflow, the 4bbl is no advantage, even if it opens right after idle. Because......... any carb only flows what the engine asks for. So in effect, if the tires don't spin, you may be waiting until around 3000 rpm, maybe even higher. With an A999 and 3.21s , that's gonna be maybe 25mph in First, and 50 or so in Second gear .
So while the TQ may be moaning it's heart out, until the engine starts pulling more air thru it than the current carb/intake allows, that moan is just a moan, lol.
If you already own it, and you have the ambition, install it; cuz with the right rear gears, you will get a lil power for passing on the hiway.

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This was years ago I removed cats as I wrote with canadian y pipe and moved gas tank over a notch and added dual exhausts. Also yes nothing down low really as I wrote but later something kicked it in butt and I could feel the extra power. Again, no powerhouse ground pounder but with the extra air out the extra air/fuel in was helpful. Admittedly the sound was a big part of the appeal as well. Swapping gears is a big help especially with the dog 2.2. All my M Bodies after were AHB's with factory 4bbl and 2.9 gears.