compuvette

O.K. guys, I was looking through my Edelbrock catalog and had an idea. I was originally going to leave the outside of my 270HP engine looking stock (stock manifold, carb, exhaust man, etc...) but then I saw the Edelbrock C-26 dual quad manifold for SBC. I looked at the manifold size and it is shorter than the Performer by about one inch and the oval dual quad air cleaner is three inches high. I am betting that it would fit under the hood. I thought that it would look really cool and would give me good power with two 500cfm Edelbrock carbs. They sell a fuel line kit and a progressive throttle linkage for this manifold. I have 487 heads that I think have 2.02 valves (have not taken the engine apart yet) and will be installing a Crane Blue Racer 284H cam (218 deg. at .050 and .450" lift). I will also be running 9.7:1 compression with some Kieth Black pistons. I am planning to use the rams horn exhaust manifolds with this combo. I thought that they would look cool with the dual quads and the finned "Classic" Edelbrock aluminum valve covers. Desktop dyno estimates about 365HP and and 375 LBs with this setup. With the Qjet it would be 335HP and 365LBs. What do you guys think?

EricU

One of trhe magizines just did a dyno comparison of a bunch of different intake/carb combos. If I remember correctly the low rise dual quad didn't do as well a good single carb set up. I will try to find that article.

Eric.

yellow 72

January issue of HOT ROD :smash:

45ACP

http://www.idavette.net/hib/BBfHInet14.htm

81vette

I've been dreaming about the 2x4 setup from Edelbrock for the past 3 months (saving every spare dime). I hope to order it next month. Scoggin has a kit for about $780 with two 500cfm carbs, manifold, air cleaner, fuel line, linkage kit, intake bolts, gaskets, and carb bolts. I haven't called anyone else on the price, but Summit may have a good deal as well. I think this setup should work really well on your car, not to mention look really cool.

I saw the Car Craft article about the 2x4 but it was on a Ford 302 engine, so that explains the loss in power. :D Seriously though, this setup is rated 1500-6500 RPM, and there's no other manifold/carb setup that I know of that will fit under my stock hood and provide that kind of RPM range. It can be setup to run off the back primary only, so gas mileage should be good as well. And with 1000cfm it will provide more than enough flow for a 350 SB. I really can't see a compromise in this setup, but maybe someone else can chime in here with a difference of opinion.

Update: Well I read the BBfH article, and now I'm bummed. :cry :cry :cry


[Modified by 81vette, 10:32 PM 12/21/2001]

tsw71

There is little doubt that the newer single four barrel intake designs are better than some of these old setups, BUT the dual quad setup is just so damn cool to look at that it is almost worth giving up a few HP. I almost bought the edelbrock dual quad intake for my 71, but when the cost is 3 times the price of a single plane, it makes the switch a little hard justify. In my case, I already have a pair of Carter competition series 500 AFB's that I bought to use on a future project car. I also run another pair of these same carbs on my street rod sitting on top of a tunnel ram. I may be able to make more power on this motor using a more modern Victor or other high rise intake, but it's hard to beat the nostalgia look this setup provides. If you plan to do a lot of racing, then go with what makes the most power. It the car is for your own enjoyment, then who cares if it makes 15 HP less @ whatever RPM. You will most likely not even notice the difference in power unless you start comparing timeslips, but you will notice how good it looks everytime you open the hood. :cool:





[Modified by tsw71, 9:40 PM 12/21/2001]

Jvette73

Awsome idea!! I bet dual 390cfm's would be more then enough. Better vacuum and intake velocity with the smaller carbs.

robert kirk

i have this set up on my 71 bb. love it, looks good and response is great. robert

gkull

2X4 are great. The look. When you have a restrictive exhaust it's better to use something with a a split duration like the Crane 272 Power max. Wider lobes and with closer to 400 hp.

compuvette

Robert, how much of a pain was it to tune the carbs? Did Edelbrock tech support give you alot of help? Do you get hideous milage? I am planning on driving this car on a few road trips this summer if all works out well (Corvette Museum, Mid America, etc...) and I want to make sure that it is fun to drive and will not cost me a total fortune to drive! I am running 3.08 gears and am not planning on replacing them. Thanks for the info.

mountainmotor

I have looked into this before and they will fit under a 74 hood.I don't know about a 71 though.I have seen this set up with sharp throttle response on a 383 10.1.
Compuvette.Please don,t take this wrong but I believe you will be really diappointed in that cam you are going to use with the 3.08 gears.No matter what manifold you use.There is a Crane that I have used before with your set up that works really well.In fact it is the type of cam that would optimize the use of the short runner dual 4 manifold and would work w/o headers.I think you are on the right track if the hood will shut with the set up.

mountainmotor

Jvette,
390's won't physically fit that manifold. They are a little too long.

Alwyn678

You will absolutely love the cam with your set-up and with the 3:08 gears...I know I love mine!!!by the way I am running stock rams horns through Flowmasters and the sound is FANTASTIC...I say Go For IT


[Modified by Alwyn678, 8:52 AM 12/22/2001]

mountainmotor

He uses my recommended cam and all else equal he is going to leave on you hard in a drag race:D

Alwyn678

Whatever I Highly doubt that ......My motor was built very well and the cam was recommended by several builders....... mountain man


[Modified by Alwyn678, 9:02 AM 12/22/2001]

mountainmotor

My user name is mountainmotor.Your remark is no way to make friends on the forum but is a great way to recieve no help in the future.You have no idea as to who you are talking to nor my credentials and what I have accomplished in 30+ years of motor sports.I have forgotten more than you will ever know about engines and before slamming me again you might want to talk to ganey about who I am and what I know and have accomplished.
I will buy this member the cam I have talked about if he will put it in his car to teach you a lesson.Obviously you would be in a bind without the forum support and you don,t get a second chance to make a first impression.

tsw71

Your right foot will dictate the milage you get. On my tunnel ram setup, I did not bother with the costly progressive linkage. Mine are connected by a rod to open up together and it works fine. Since the Carter/Edelbrock carbs are vac secondary and the primaries are fairly small, the progressive linkage is not absolutely necessary. Going wide open throttle from a dead stop will be no different than doing the same with a single four barrel with mech secondaries. Tuning them is very simple. The nice thing about these carbs is the ability to re-jet without removing fuel. Carter(and maybe Edelbrock too) sells a "strip kit" that will come with an assortment of jets and needles. The needles are very easy to get to and change. One screw up top to get each one out. Becuase of the needles, you can easily tune the primary curcuit without even taking the top plate of the carb off. The only tricky part (and it really isn't that bad) is getting the idle curciuit set up when running them like I do. You will need to play around with all four idle screws and a vacuum guage to get it right. Once you get them dialed in, they will work perfectly.

Tom

81vette

Has anyone running Carter/Eldelbrock carbs experienced the problems discussed in the BBfH article link above? It said they were having problems with erratic air/fuel ratios at idle, and problems under hard cornering and braking. They did say that they ran a better time in the 1/4 mi. with the 2x4 than the single setup though.

compuvette

Mountain, Alwyn, please play nice. I did not mean to cause any havoc with this post. I just want to see if I can get something that will run well and still look cool. Mountain, could you send me the number on that Crane and I will look at it and discuss this with my engine builder. If you don't want to post it, just send me an e-mail. I just bought the 284H recently and could still return it. I assume that you guys looked at the .050 duration on this cam that I posted above. It is advertized as a 284 but it has specs closer to a 272. I am also thinking about using 1.5 rollers on the intake and 1.6 rollers on the exhaust. I'm not 100% sure witch cam I will use yet, and want to try and get the right setup the first time. P.S. Merry Christmas!!! :chevy :flag


[Modified by compuvette, 4:14 PM 12/22/2001]

Chuck Harmon

Compuvette,

Although it wouldn't work for a mild engine, I strongly recommend the STR-10 Eddlebrock crossram manifold. A copy of the Chevy crossram manifold used by Mark Donohue to win the Trans-Am series in 68-69 with his 302 (305 actual) smal block. I ran this manifold on my built 355 small block and absolutely, positively loved it!!

The look on faces when opening the hood was almost worth it alone! It fit (but not well) under a LT-1/BB hood. Using a 73-79 hood would be a better choice. This manifold really needs double pumpers to work well. The new 390cfm 4150's would be perfect today if you can find this discontinued manifold at a swap meet.

The "How to Hotrod your Small Block Chevy" books has a copy of a Chevy dyno sheet with Donohue's motor, 475 horse power! I copied this engine with over the counter factory parts. All balanced and realistically blue printed. The only exceptions: larger 355cid, better 2nd design angle plug heads, STR-10 manifold (instead of unobtainable and virtually identical factory piece). I should have made at least as much power, perhaps more. People couldn't believe this car didn't have a big block!

The only thing in my book that was better was an L88. One day I came across this...

Chuck