Which Dual Quad Carbs for 392 Hemi?

I am currently rebuilding a 392 hemi. It will be mainly for the street, with the odd weekend race with the nostalgia group up here in Canada.

I have the Weiand 7263 manifold for a dual quad setup.

Which carbs are people running and/or what do you recommend?

Any assistance would be welcome.


Thanks,


Joe

 

where about in Canada

 

I'm building a 392 with the same intake. I will be using two 625cfm new style AFB carbs.
500cfm carbs would be more suitable but I've learned it's still fairly difficult to overcarb an engine with the weighted valves above the secondaries on these carbs.

 

I am in Hamilton Ontario.

 

The Carter - same as Edelbrock - 500 cfm's on my 462" Buick work well.


Very easy to tune and the 'tip-in' with straight linkage is very smooth.

Idles at 600 rpm with a cam that's 288-292 advertised duration.

When I lived at 350' altitude the only tuning done was to swap metering rod springs to match the cam.


When the 31 on 32 frame roadster it's on now gets running I'll probably have to lean it down two steps - as per the Edelbrock manual* - since I now live at 3400'.




Took the 750 cfm Edelbrock on my 32 roadsters 462" BB Buick down two steps leaner and it runs great here as well as at the 500' altitude down at the river.


BigBlockMopar's right about a too-large Carter/Edelbrock being very fogiving in the overcarbureted dept.

A few months back my pals302 Ford powered 46 Ford sedan sunk a float on the 600 cfm Edelbrock.


We trailered it back to his shop and put my jetted for sea level Carter 750 on it in about twenty minutes, fired the car and went to the Saturday car show segment of the Route 66 Fun Run.
The car ran great, no problems.

He ran it for a week until he got new floats.

 

Very nice...........thanks

 

Carter AFBs are a good choice somewhere in the 600-700 cfm range.

If you want a pure get down the track carb then I might look at a pair of Holley 660 Center Squirt carbs. But they are a lousey street carb..

 

Cool, I am in Stoney Creek.

I would recommend a pair of 500 Carters or Edelbrocks. My brother had a pair of Carter 500 comp series on a 400 Mopar with a 284 degree cam and they worked very nicely.

 

Fwiw, when I first built the 32, Kenne-Bell (Buick speed shop and guru's) recommended a pair of 750's.

I opted for a pair of 500's since my aim was a torquey and quick responding engine.
It worked out well.
I have a pair of 750's to try if I get curious - and I may since the 31 has a drag race style suspension in the rear.

If you're running on the street, do opt for the 500's, but if you stumble into a deal on a pair of 600's or even some good - but discontinued 625's - grab em.
They'll work fine.

 

The Factory used the Carter AFB's. I have a set that came off of a 392...one with choke, one without. If you're interested, shoot me a PM...

 

I'd say two 500s would do well on the street or strip

 

Two 500's is plenty. If you are lucky get the factory 61-62 AFB's for Chrysler. they work good. Not trashing Edelbrock here but mine always seem to run rich over time. Find the early small top AFB's you'll be alot happier over time.


Tim

 

Thanks for the suggestions.

Has anyone tried dual Holley carbs with the appropriate adapter plates?

 

Go tradtional, wcfbs, afbs, or holleys

 

If you use the Edelbrock's just lose the neon sign on the front that's a dead giveaway that it was built in the 21st century. They just stick out like a sore thumb to me and kill the look. JMHO

 

i gotta tell ya , i didnt listen to BOB at hot heads , or a friend with a 392 2x4 set up when they told me to get rid of the 750 edelbrocks , get 2 390 holly carbs , bolt em on and hold on when you stab the throttle . guess what ? they were correct . i had 2 750's with a single plane intake (cant use progressive linkage on a single plane) and it ran , but shitty . i put the 390's on and holy shit , runs like a scalded dog and gets 23 mpg on the highway . i should have listened to the 2 smart guys from the begining .

 

I would suggest 2 comp series 500 cfm AFB's.

 

Nice setup

This is a tough decision, as everyone has their own personal favourites.

 

A few people have recommended the Holley 390's to me.

They might be worth a look.

This has turned into a pretty interesting topic (for me anyways).

Again, everyone seems to have their preferences.

 

The new AFB clones will not have even a close calibration for the 392. For really good performance, you would need to change primary and secondary jets, step-up piston springs, metering rods; and modify the primary clusters AND the angle of the auxiliary air valve.

For street use, find a MATCHING BY TAG NUMBER pair of Pontiac carbs from the early 1960's from Pontiacs with automatic transmissions. Which pair you choose is less important than the fact that both are the same number.

The Pontiac carbs are from 550 to 610 CFM (and can easily be changed to 610 CFM). The Pontiac calibration is extremely close to the Chrysler. You should be able to bolt them on and go; maybe have to change the primary jets, but I doubt it.

I would suggest running chokes on both, idle on both, and run solid linkage; but this is a matter of preference.

Of the above modifications mentioned, the airvalve is the most critical. If you use the original airvalve with no modifications in the clone, expect a hesitation when the secondary kicks in.

Jon.

 

Practically identical to the first holley 4 bbls that came out in '57 i belive, that'd be my choice

 

I found a pair of 390 Holleys in excellent condition and they are on the way. From what I am told, they were running 3 weeks ago and don't need to be rebuilt. (I might do it anyways)

Thanks for all of the suggestions.

 

Tim,
I have two 1961 3249's AFB's. They came with no weighted air valve, and small primary and secondary throttle blades (equal size). I am curious why you say these are a good dual quad combination? I am trying to apply these as dual quad to a hopped up 354 hemi.
Godspeed

 

Hi, it's going on 11 years since you originally posted this thread and I would love to know which carburetors you wound up using? I'm in the same boat you were in and I'd really like to know!

 

Profile says he hasn't been on since June of 2020.Hope he's ok.

 

Got a pair of these last year, they are 650CFM, probably to much for this 331 but they look good. Not say'n this is what you should get, just show'n ya what I'm runn'n and how they look.

 

And now for something completely different. I have a Weiand dual quad manifold on the 331 in my dirt modified. I couldn't it it to perform the way I wanted with 4-BBLs and ended up putting 2 large base 2G's on it using the appropriate adapters and straight linkage. It runs great, starts easily, responds well, and seems to have plenty of power. I will have to say that it is a highly modified engine with 12.5 compression, an Engle roller cam and other goodies, and it is used only for oval track racing. I have had many carburetion set-ups on this car, from four 97's to a 500 Holley competition 2-BBL, and it runs best with this one.

Just throwing it out there.