318 Intake and Carb Advice

Farquiaj

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Hi All!

I am looking for a little more power out of my stock 318. I have a 74 Charger with a 318. The only thing I have added is duel exhaust. I am looking to get a little more power WITHOUT changing the cam. Any recommendations for what kind of intake and carb I can swap out? Looking to add a 4 barrel carb.
 

Ron H

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Depends how much you want to do. I added duals, a 4bbl, electronic ignition (you probably have the latter) and sure-grip end to my poly years ago before complete rebuild much later and it made a noticeable difference with giddy-up. My old carb was out of a mid-60's 383 as I can recall and now have a 650 Edelbrock (factory 4bbl intake from the era).
 

YY1

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Easy answer-

Edelbrock Performer 318/360 and Edelbrock 500-650 CFM AFB or AVS, the AVS being the more versatile and economical.

Buy them new today for under $1000, or hold out to find them at swap meets, or here for several hundred less.

Very common parts.
 

BigBlock61

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Edelbrock RPM duel plane manifold and a 600cfm vac secondary holley is what I'm running on my 78 Magnum with a 360 and it runs great. I'm at the point where I need to either add a shift kit for the 904 or a cam. Dont over carb and unless you are going to put in a cam I'd probably stay away from a double pumper.
 

Rusty34

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The Edelbrock and 600 CFM Holley mentioned above is probably the best answer but if I were doing it I would like to do it with stock parts. I would try to find a Thermoquad, manifold and air cleaner from a 72-74 340/360 and use factory parts for all the connections. I would recurve the mechanical advance in the distributor (lighter springs) to get timing to advance a little quicker. I would seriously think about headers and I would change the rear gear ratio to 3.55. Also if the budget permits a little later on you would be surprised at how much a difference a step up in torque converter stall speed RPM makes. You might want to do the cam after that and I would recommend the Chrysler "Purple Stripe" street grind.
 

rumblefish360

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Hi All!

I am looking for a little more power out of my stock 318. I have a 74 Charger with a 318. The only thing I have added is duel exhaust. I am looking to get a little more power WITHOUT changing the cam. Any recommendations for what kind of intake and carb I can swap out? Looking to add a 4 barrel carb.

Been there, done that….

For sure, ether a factory 4bbl intake (CHEAP!) or a Edelbrock Performer. Not the RPM.
(The RPM does work very well on my 5.9 w/headers as the only upgrade but not as great on the smaller 318, IMO, skip the RPM for your application.)
OR if you can find an Edelbrock LD4B. A Weiand Action Plus would be my last choice and intake fitting the job description above. I would not bother with other intakes myself.

On a carb, a factory TQ is the best performer easy, BUT! The tuning rods and jets are ether stupidly expensive in kits found on EBay or just expensive part to purchase by part by part on a new purchase. I also would not run any TQ ether. It would have to be an early one or a truck carb. The lack of vacuum ports is what your after. If you can source a good TQ without an EGR vacuum & purge port found on the base of the carb, those are the ones I would use IN ADDITION TO a small primary @ 1.38.

Enough of the TQ. On to what is currently available and new, along with tuning parts at the ready.

Through testing myself, I have personally mounted (Both 600 cfm carbs) a Holley 1850, a Edelbrock AFB. Both performed equally on my ‘79 - 318 with only headers and a Crane cam @ 218/226-.454/.480-112.
(The duration @.050 works well with a stock converter FWIW.)
A very mild cam indeed. Besides an orange box ignition, all else was stock in a ‘74 Duster, 904/3.21 gears on stock tires.

Choose the carb your most familiar or comfortable with.
Just use a thick gasket under the carb to keep it cool so the fuel doesn’t percolate. This gasket can be sourced from Edelbrock. There around .333 thickness or so.

What gear ratio and tire size does the car have?
What’s the cars weight?

The next improvement in acceleration would be gears and a higher stall torque converter. A good quality converter can have a stock feeling when driving. Even at a 4500 rating. Not that you would need a 4500 converter! LOL!

Should you ever do headers, only bother with Doug’s headers, best for your application or TTI headers, for a more robust and aggressive engine.
 

Rusty34

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@rumblefish360: Thanks for mentioning the truck TQ! Would a truck TQ be a little more responsive on a smaller engine? And I will take a look at the Edelbrock Performer too. You should be able to get a 318 a little over 300hp without too much trouble.

Oh, what about a 340 windage tray inside the oil pan?
 

rumblefish360

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@rumblefish360Would a truck TQ be a little more responsive on a smaller engine?
A truck TQ is the same as any other TQ save the jets and rods. The year of the carb and what it came on can dictate how many vacuum ports are on the carb to meet the emissions standard of the year and model. I’m s likely you’ll find them with a 1.50 primary. I haven’t tried the 1.50 primary on a 318, just the smaller 1.38 model.
Oh, what about a 340 windage tray inside the oil pan?
What do you mean “What about….”
Installing one is free HP. Chrysler said it was worth 15 hp on a 340. While it’s probably less on a 2bbl. 318 thats mostly stock since it is making less power to start with, It’s something that I would do if I had the parts on hand.

I look at this way, if the OP’s ‘74 a 318 is making its rated 150HP, adding a 4bbl and dual exhaust is worth an easy 35HP, if not more. If we add just 10 more for the windage tray, because the engine is making less power, now we are at a 45HP gain, at least. All for just swapping out 4 main cap bolts and screwing on a curved metal tray. Sure! Why not?
Just open up the louvers until level for max oil drainage.

Perhaps these TQ video can help a little bit?
https://m.youtube.com/channel/UCkh-DKdDi3iUrXKG-duM72A
 
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Rusty34

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What do you mean “What about….”
Installing one is free HP. Chrysler said it was worth 15 hp on a 340. While it’s probably less on a 2bbl. 318 thats mostly stock since it is making less power to start with, It’s something that I would do if I had the parts on hand.

I've got to replace the oil pan on a 318 Charger I just got and was thinking I should add the windage tray while the car is up in the air and I am in there. Stock 318/340/360 pans do not have baffles so it would be a benefit at higher RPM. I haven't looked yet to see what parts are affected but I'm guessing I will need to get 4 special main cap bolts and nuts to mount the tray.
 
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rumblefish360

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Yes, IDK if it’s available through MoPar anymore. But you’ll need the windage tray, 4 main cap bolts that are drilled on the head to accept 4 small (1/4 X 20 IIRC) attaching bolts that secure the windage tray.

Yes, power was found on the big end. But it does have another help thing to it. I’m stops the oil from being whipped around over and over beating up on it, which slowly degrades the oil. The oil has less foaming and aeration which helps maintain a longer life and better oil pressure.
 

rumblefish360

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Your welcome. If there’s any other TQ questions, ask and I’ll try and answer them.
 

Rusty34

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OK, can you advise me which 4bbl intake and TQ I should look for for my 71 Charger 318?
 

Ron H

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Posting earlier on my poly re-do, I changed out the 3:23's to 3:55's and didn't find any notable difference off the line; but a few hundred rpm increase at cruising speeds I'd rather do without considering my thrill is riding in the country with a few car buds. Motor's bored .60, mild cam, headers, solid lifters, later edition TQ around 2400 stall. OD would be a nice feature..
 

rumblefish360

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OK, can you advise me which 4bbl intake and TQ I should look for for my 71 Charger 318?
I believe I have already made the suggestions in my first post above in this thread. I’ll not repeat myself.
 

Rusty34

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I believe I have already made the suggestions in my first post above in this thread. I’ll not repeat myself.

Ahh, yes you did. Sorry about that, my bad, all I had to do is READ! I will start looking for those parts.
 

YY1

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The trade off with the TQ vs the AFB/AVS is the maintenance.

There's almost nothing inside the AFB/AVS, making it super easy to disassemble, clean and adjust, plus the rods and jets are available new.

While the TQ offers smaller primaries and potentially huge secondaries, note that most of the adjustment procedures begin with "remove carburetor and turn upside down".
 

rumblefish360

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In tuning with jets, yes, rods still are able to come out of the top. Still like the AFB/AVS. All 3 float adjustments are the same, take off the top and flip.

The only maintenance on all 3 carbs I have ever needed is to keep the air bleeds clean and clear. Handled with brake cleaner & a quick spray. No disassembly needed.
 

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