Smallblock 2x4 setups

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Captainkirk

Captainkirk

Old School Mopar Warrior
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I'm interested to know if anyone out there is running a smallblock street/strip dual quad setup, what equipment they're using, how they like it and how it performs (ET's, tuning, etc) as well as cost info. Any comments would be welcome.
 
It's very hard to find one much less an owner running one.

Offenhauser makes an in-line set up. I have never seen one in person or in the mags.
 
Like this

MVC-019F[1].JPG
 
I have an Edy Street Tunnel Ram with 2 600 holley vac. sec's on my 340. It is no longer made. It is a little shorter than a reg. tunnel ram. I bought it at spring fling for a great price with carbs and linkage. It was already ported and the carbs worked over. I did a little more work smoothing out the inside of the intake and replaced my strip dominator and carter comp. series 750 carb with it. I broke a shifting fork not long after I put it on and it still is down but it seemed to perform a little better. I love the look though. I love seeing anything sticking out of the hood on muscle cars, especially Mopars!
 
You can get the manifold through Perfornace Automotive Warehouse (PAW) or through SoCal. Bear in mind they no longer make the large port manifold for the 340/360. They still have the 273/318 manifold for 66 and up and a separte manifold for the 65 273 which has the different bolt angle.
 
I found an Eddy D64 manifold for sale. Owner says it fits smallblock Mopar. Any feed back on this?
 
Captainkirk said:
I found an Eddy D64 manifold for sale. Owner says it fits smallblock Mopar. Any feed back on this?
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I would try to check with Edelbrock to find out the correct application. This is just a guess, but the D64 makes me think it is probably for early (64-65) 273 heads. D=dual carb, 64= 1st year it fits. The reason is I think with the Dual plane manifold they used a progressive type of numbering. D4B= dual plane 4 barrel, for early 273 heads. LD4B= late dual plane 4 barrel, for late 273 & 318 heads. LD340= late dual plane 4 barrel, 340 head port size.
 
Thanks! That's exactly the kind of info I was looking for. I guess I'll hold off until I know for sure. I've made $100.00 mistakes before because people don't know what they have or what it really fits.
 
i'm a little late here, but i sure do remember a very reputable magazine with initials MM wrote about none other than mother mopar having some 2x4 set-ups.
i think they may have been for w-2 heads, but they were still available.
 
As said before:
Offy has one for the 273-318 Part# OFF-5615

Weiand also has one.Part#WEI-1995
Fits Chrysler "A" engines.This intake is a high rise.All info from PAW catalog.
 
Yikes! Those suckers are pricey. IMHO, since the low rise version is only availible with small ports (273-318) and with AFB mounting pads, I would think that a 750-850 double pumper Demon carb on a well designed dual plane would perform just as well if not better up to 6500 rpm, even on a stroker. Of course, you would be missing the dual carb cool factor. :)

I think the low rise dual carb big block version might have some merit with a couple of 450 Holley/Demons mounted on it. It would be sized more to the engine's needs, keeping velocities up in the venturi's while improving cylinder to cylinder mixture distribution.

Comments anyone?
 
Wellllll, the cool factor is where it's at with those itakes. I wouldn't mind doing one. It'll make power for ya. It may not make a RPM air gap and Demon look silly, but it'll do well. It would be nice if both carbs were well centered between the runners.

I also wouldn't really go under a pair of 600's on a big block unless the dispalcement was small or mega high torque is the goal. The big block can suck it down. Pump it up a bit and a pair of 750 are good to go.

(Small block torque maker = 2 X 390 holley's, hot street, 2 X 500 cfm.)
 
1500cfm? Really? According to my calculations, a 440 turning @ 6500 rpms will only pull 827 cfm at 100% volumetric efficiency. Granted, a well set up race engine will pull better than 100%, but even at 110%, a 440 would only pull 910 cfm.

Of course, if we're talking stroker big block blocks turning 7500 rpm, that would be a different story.

Whats your theory on this Rumble?
 
Has anyone tried a 2X4 setup using ThermoQuads? Seems like it would be tailor-made for a tunnel-ram setup, what with the small, torquey primaries and the monster secondaries. They'd snuggle up close together as well, unlike Holleys which often have to be turned sideways. I'd love to do a couple of these on a low-pro manifold, but haven't found one that would fit 2 TQ's yet.
 
Captainkirk said:
I'm interested to know if anyone out there is running a smallblock street/strip dual quad setup, what equipment they're using, how they like it and how it performs (ET's, tuning, etc) as well as cost info. Any comments would be welcome.
Click to expand...

Maybe this is of interest to you from the local Buy and Sell.
I was interested until I went Eddy head Magnum setup.
DODGE 318/360 EDELBROCK TUNNEL Ram - w/ 2 Edelbrock 600 cfm carbs. Will separate $600.00. obo. Calgary. Tel: 403-245-8730
 
Captainkirk said:
Has anyone tried a 2X4 setup using ThermoQuads? Seems like it would be tailor-made for a tunnel-ram setup, what with the small, torquey primaries and the monster secondaries. They'd snuggle up close together as well, unlike Holleys which often have to be turned sideways. I'd love to do a couple of these on a low-pro manifold, but haven't found one that would fit 2 TQ's yet.
Click to expand...

Hmmm....TQ's are rated at 850 cfm. x2 would be 1700 cfm. Little overkill for a small block don't you think? I would imagine that once the secondarys opened the venturi velocity would drop like a rock, which would as result in a severe lean condition.
 
Whats your theory on this Rumble?
Click to expand...
I have noriced that cfm formulas are not on line with what the car will do at the track.
Hmmm....TQ's are rated at 850 cfm. x2 would be 1700 cfm. Little overkill for a small block don't you think?
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Engine set up dependent. I have seen old pictures of small block set up like this for compotion useage.
I would imagine that once the secondarys opened the venturi velocity would drop like a rock, which would as result in a severe lean condition.
Click to expand...
No, because you would tune the carb for such use. YES, velocity would drop, but then again on a race intake and numericaly really high gears, it will not matter much.
You can also tune when the door opens and how much it opens alittle bit.
The smaller T-Q's are said rated @ 800. The primarys are smaller.

388dart, redrill the Magnum heads for "LA" intake useage and port the hell out of them.

Captin; I'd love to do a couple of these on a low-pro manifold, but haven't found one that would fit 2 TQ's yet.
Click to expand...
And you probably won't. BUT! Welcome to the world of hot rodding. Now your into custom work. I think it is Offenhauser or Mr. Gasket make off set adapters of such use with Holley carbs. It isn't really the carbs pad thats a challange, it's fitting the 2 T-Q's next to each other. If it requires a small off set, thats where the work comes in.
Start with a couple of basic spreadbore to square bore adapters and start cutting and modifiing them to fit. Once you get it to fit, go to a peice of aluminum stock and cut out the shape from the template you made out of carb board and cut up adapters.
 
Offy made or still does make 2x4 spreadbore intakes.

When you run dual 4's you don't add up both carbs to determine the cfm of the carbs to use, it does not work that way. Look at the 340 6 barrel and 6 pack they have approximately 1050cfm if you add up all 3 carbs and this is a stock motor. Like rumble says it is set-up dependent.

Don't get to caught up in formulas, equations and dynos (both computer program & mechanical) etc. These are just tools and guidelines after all we race and drive cars not formulas, etc. There are way to many variables for a formula to work 100% correct. For that matter on a dyno it only reads torgue, your horsepower is a formula of your torque and rpm.

Something else that can be done if it is street driven alot is use progressive linkage. Buick did this on their 2x4 setup on their nailhead 401 and 425. These engines ran off the back carb during part throttle cruise because the primaries on that carb are closest to the middle of the intake. When you got to about half throttle the front carb started to open up and of course if you mashed the throttle both carbs were open fully. Being the carbs have different opening rates the front carb had the linkage mounted closer the throttle shaft than the back carb because it needed to open at a faster rate than the back carb.

Chuck
 
I do not have an offical Offy site, but you can click this instead; http://www.offyparts.com/index.php?osCsid=eb79eb72db384df7161ee4f72e4bd1d5

The inline dual quad intake pictures do not show a difference beteen the low rise and hi rise intakes. The low rise is piuctured.

Offy also used to make them in both port sizes. Now only in the smaller port size at this site.

Double check with P.A.W. in Cali. for there stock.
 
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