FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: mbrunson427 on February 06, 2018, 09:39:44 AM
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Last week I got my hands on an adapter that someone had made for the Edelbrock Air Gap 2x4 intake, to allow Holley carbs. After mocking up the carbs and a distributor, it's pretty obvious that this one isn't going to work. My neighbor is going to machine one that pushes the carbs further back on the intake, and allows the distributor to fit.
If I'm going through the trouble of having this done, are there other people interested in one? The neighbor is retired and I don't think he wants to do a krillion of these, but I'm sure I could talk him into doing a batch of them.
(https://s18.postimg.org/yl087tnux/IMG_4427.jpg) (https://postimages.org/)
(https://s18.postimg.org/k1t36fa5l/IMG_4428.jpg) (https://postimages.org/)
(https://s18.postimg.org/bjjn22vx5/IMG_4429.jpg) (https://postimages.org/)
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By pushing the carbs back far enough for the distributor to work, you'll be pushing the rear carb past the primary venturi's. Not sure how you plan on making that work, but even with a 'contoured' adapter to get the airflow back into the plenum, it'll be FAR from optimum.
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Working on one here. Similar in concept, except that mine will require a trip to Marcella's to get some welding done - and then another trip into the mill to rearrange things a bit. Still not certain its economically rational - but gotta try something.
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As above, I think it depends on how well it works, and cost. If it works well, performs there will be interest for sure.
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The idea we had going would be to contour the venturi's back to the Edelbrock position. As stated, it would be less than optimal, but it would work. I didn't figure that everyone would want to, or care to, go through the headache of welding.
In my situation, I would take the manifold and try to lay those openings back and shift the position on the intake, and weld back in where necessary. This plate would be a starting point. Basically, trying to do the best I can with the real estate available on the plenum. To do the optimal "right thing", it'd require some major welding to the rear of the plenum and work to the #4 and #8 runners, and maybe even #1.
Barry, I'm sure your deal is pretty much the same. Not too many ways to skin the cat. I wanted to make a "one size fits all" plate that could work for everyone, and for those of us that care to go further, we could. With my luck, the un-modified intake and plate would actually turn out to make more power than the one I spent all the time on, because of some Eddy current super sucker tornado effect or something :o.
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No
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Yes , I have been wondering about this for awhile now , glad to see someone doing something about it , thanks to all of you .
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Here is a paper pattern of a medium riser carb layout over the Edelbrock intake. If you want to keep the front carb oriented in somewhat of the same place as an original MR 2x4 intake, this is what it's going to look like. It would be a pretty easy mod if the runners of the two intakes were oriented in the same sequence, but they're not and because of that, it makes things much more difficult.
(http://www.performanceboats.com/gallery/data/500/medium/IMAG9393.jpg)
You can see that even when keeping the carbs symmetrically spaced over the Edelbrock openings, it's not a slight offset. Moving them either way, forward or rearward, is going to make one end really exaggerated.
(http://www.performanceboats.com/gallery/data/500/medium/20046085_10211984272275704_1587296391_n.jpg)
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That picture really illuminates the issue. It's not a small mismatch as far as I can tell. I don't think I'd want to do that in any circumstance. Maybe the "cure" is worse than the "illness"?
JMO,
paulie
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Sometimes 10 lbs of spuds won't fit in a 5 lb sack.
If you have to run Holley carbs on that intake then run them sideways and spend your time building the linkage. If you just don't want to run the Edelbrock/AFB type of carb then use two throttle bodies.
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The pictured adapter is similar to the HotHeads one but theirs looks taller. I was thinking of using it with a low profile distributor to fit under the front carb. Haven't got one or tried yet
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Turn the Holley carb sideways...
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Couple of these?
Available from Summit.
"Description: Offenhauser carburetor adapters are designed to allow you to mount most any carburetor on most any manifold, saving you the expense of buying a different manifold or carburetor. Made from cast aluminum, they will provide a smooth transition from carburetor to intake for trouble-free operation."
Don't really understand the fixation with making this intake work with Holley carbs...
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Turn the Holley carb sideways...
Doesn't work on a dual plane intake.
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Or go with Weber's...
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Looks like after adapter are tweaked for Holley's then horsepower level going to drop right back down to EB's because of the goofy angles , seems like a lot of work to make a manifold fit a carb it's not designed to fit
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Scott, measure from the thermostat face to the front carb stud of your medium riser intake, then position your template in that same position on the edelbrock intake. What I measured placed the template 1/2"-3/4" more forward than where you have it. I was trying to nail down the carb position perfectly to avoid having issues with the distributor and expansion tank in the front or the firewall in the rear.
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Scott, measure from the thermostat face to the front carb stud of your medium riser intake, then position your template in that same position on the edelbrock intake. What I measured placed the template 1/2"-3/4" more forward than where you have it. I was trying to nail down the carb position perfectly to avoid having issues with the distributor and expansion tank in the front or the firewall in the rear.
I was pretty careful about my references but I'll re-check. From my notes;
From vertical water neck plane to center of front carb stud holes; Edelbrock, was 4.885", my medium riser was 4.705". Only roughly .180" difference.
Edelbrock carb pads sit @ 3* angle, medium riser @ 4.9* angle.
The Edelbrock carb pad plane intersected the vertical waterneck plane @ 4.975" high, the medium riser carb pad plane intersected the vertical waterneck plane @ 4.07".
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I'll fiddle with it some more this weekend too. Neighbor Joe is supposed to come over and take a look.
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"Don't really understand the fixation with making this intake work with Holley carbs..."
Its the least expensive dual quad intake by a large margin and is readily available, and the quality is good.
Somehow the Carters are uncool.
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I'm a Holley guy, but are two 750 or 800 Carterbrock carburetors that bad?
Or is it the appearance of them? Heck, a 426 Hemi still looks cool with two Carters on it.
paulie
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I have yet to see, or hear of anyone dyno testing that intake manifold with two 800 Edelbrock Thunder series carbs. Everyone uses either the 500 cfm, or 600 cfm street style carbs. I ported one of those manifolds for a forum member about 20 years ago with a pair of RPM heads. He installed them in a roadster with ported shorty headers that I did, and proceeded to break his C-6 transmission from the torque. I believe it will be a very strong intake with just a clean up and two 800 cfm Edelbrock Thunder carbs.
As for that spacer/top, if you were to mill the entire top off the carb pads and just expose the top runners, then you could probable center it for a much better placement with a spacer and then your carb pads. Joe-JDC
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I'm a Holley guy, but are two 750 or 800 Carterbrock carburetors that bad?
Or is it the appearance of them? Heck, a 426 Hemi still looks cool with two Carters on it.
paulie
I think part of the problem is the fact that the factory used Holleys and trying to keep the original appearance. Hard to use an original oval air cleaner with the Ede intake. A base could be made, but that's just another minus.
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I believe it will be a very strong intake with just a clean up and two 800 cfm Edelbrock Thunder carbs.
Joe-JDC
That makes sense to me, Joe. I remember this intake doing pretty well in Jay's book, even with two 600 Edelbrocks.
paulie
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I'm a Holley guy, but are two 750 or 800 Carterbrock carburetors that bad?
Or is it the appearance of them? Heck, a 426 Hemi still looks cool with two Carters on it.
paulie
I think part of the problem is the fact that the factory used Holleys and trying to keep the original appearance. Hard to use an original oval air cleaner with the Ede intake. A base could be made, but that's just another minus.
I hear ya. This just doesn't seem like right intake for the guys wanting factory 2x4 appearance anyway. I get the desire to do that especially since there is no reasonably priced factory type 2x4 dual plane intake available. But still.
JMO,
paulie
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Just a thought, but a pair of EFI throttle bodies would probably work, and fit, very well!
KS
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offy 5880 parts are made to do this summit has them.
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Dual throttle bodies would be a good solution, otherwise just stick with the Edelbrock carbs. That intake is a good match for a street rod or a cruiser. Edelbrock carbs work just fine for street rods or cruisers so it is a good match. If you want a race intake then buy a race intake. You can train a donkey all day long and it still won't be a race horse........
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Could one mill out the center and make an adapter for 3x2 bbl carbs?
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Could one mill out the center and make an adapter for 3x2 bbl carbs?
Could fill out the entire center section and use the intake port flanges to build a sheet metal tunnel ram from.
At some point you have to draw the line.
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....If you want a race intake then buy a race intake. You can train a donkey all day long and it still won't be a race horse........
Probably the best advice.
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Blue Thunder 2x4 medium risers are selling again. $995.00.
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Could one mill out the center and make an adapter for 3x2 bbl carbs?
This is where I originally started. I wanted a better performing 3x2, nobody would cough up a Dove tunnel wedge with the removable top plate (and honestly that's probably too much intake for what I'm building anyhow). The 3x2 setup has the same problem, front and rear venturis are too far forward and too far backward on the plenum. It'd require a similar adapter.
After looking at it this weekend with neighbor Joe, I think I'm going to punt. We both agreed that it'd be a better use of time/effort to make a lower air cleaner plate that adapted to a standard 2x4 top.
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The muscle car history is full of excellent 2x4 carter engines of all the brands. I had my nose in a -71 HEMI Cuda A/SA 10,71 ET European record holder for 10 years back in the 80-90 ish That 426 HEMI produced 600 HP with the old NHRA Stock rules, with a unmodified intake and Carter carbs.
Nothing wrong with Carters, the Edelbrocks lookalike you have to detail for the right application.
The 426 HEMI Carters are detailed already by the Chrysler enginers ;).
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Building a 445 stroker this way now, bj/bk carbs facing forward, should be done in about 2 months.
I do not have any height constraints so I am adding 4 hole spacers on top for distributor clearance and signal.
1" rise and 1.125" run for the angled portion of the adaptor spacers, simple ends and side pieces, using .5" spacers for top and bottom flange, easy milling and tapping, $100 buck investment and some fab time. There is some material to give on the mounting flange of the intake to make things a little less mismatched.
I'll let you know how it does on the dyno by summer.
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Our adapter is almost done. Single piece deal. Lots of Bridgeport time. Had to open up the manifold quite a bit. Its headed off to Marcella maybe later today to get some welding done - then I will need a candidate for dyno testing. Should be interesting. Might not be cost effective.
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Barry... somehow your picture didn't show?? :P
You ARE going to let us see, right?
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Yeah - I will show it. Not sure if it will be good, bad, or just weird...
Mixture distribution is a complete "who the heck knows" deal. Looks like we just evened up the six runner's effective lengths leaving the front pair long. Lengths as Edelbrock had them were already unequal, long front and rear pair and short in the center four.. Engine will probably start - but who knows from that point on.
Once we get the filler section made up for the back end we might sexy-fy the square edges a bit. But a stock or MSD distributor will fit, OE or reproduction carbs will fit, stock progressive linkage will fit, and stock oval air filter stuff will fit. John figures we can make a good drawing off the spacer now, so he could CNC the next one instead of making it up on the mill.
Been pretty busy playing catch up - four engines on dyno with a week or so, plus finishing up the final proofreading on the "new" book, and chasing parts all over creation. It's kinda good to be back at things full speed, but kinda overwhelming at the same time.
(http://i38.photobucket.com/albums/e135/Barry_R/20180215_085355_zpsj4brhpx2.jpg)
(http://i38.photobucket.com/albums/e135/Barry_R/20180215_085413_zpstswozt5q.jpg)
(http://i38.photobucket.com/albums/e135/Barry_R/20180215_085432_zpsu8u6y49p.jpg)