327 tuning dual 500cfm edelbrock carbs

Hi All..
I have a rebuilt chevy 327, .30 over bore,10.3:1 comp ratio, edelbrock performer heads, malory distributor, performer cam

I bought the edelbrock dual quad set up for the shevy small block but cant seem to tune it right, First i was told (by some friends that only run single carbs) to set it up as a one to one setup, so i did and it ran way to rich, then i was told to set it up as a progresive set up so i did that now it runs better but not right, i was told to leave the rear carb jets out 1-1/4 turns and close the front ones all the way does this sound right to anybody? should i have bolth carb jets set the same on bolth carbs? Does it matter witch carb you use as the primary front or rear? any help would be great..Thanks

Thanks, with the vacuum gage how would i get the 18-20 inches , do i go jet to jet till im there raising vacum with each jet or set one side then match the other? and can i hook the guage up to either carb or do i need to hook it up to bloth? thanks again

What size are the Edelbrocks????

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Originally Posted by DennyW

327 tuning dual 500cfm edelbrock carbs

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I certainly hope the carbs aren't any bigger then that, even at 500 CFM it's overkill on a 327......

May need stiffer /different color, secondary springs in both carbs if you are using the progressive linkage or the vac secondaries will open some before the second carb opens the primaries.........its going to take some carb tunning and linkage adjustment on this set up,its just not a bolt on and drive deal,but it can be made to run just fine with a little work.
This would be in addition to what was already posted.:D

And when it's all done, a good dual plane intake with a single 500 CFM carb will perform the same or better at considerably less cost and headaches!!!! Geez, a lot of $$$$ for eye candy!!!!!

thanks guys, for all you help, is there any difference in making the front the primary carb or should i stick with the rear?

yea i know it's a lot of $$$ but it looks so cool on my 36 coupe. Iv'e never done a dual quad set up before it is a little intimidating !!!

sorry for al the questions, say for instance if i was running a single 500cfm carb and the jet screw settings were 2 turns out in bolth sides woud i do 1/2 turn on all 4 for the dual quad set up? to equal 2 turns.

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Originally Posted by Motown

thanks guys, for all you help, is there any difference in making the front the primary carb or should i stick with the rear?

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Depends on the manifold.......is it open under both carbs..........or does the front carb feed the front 4 cylinders and the back carb the other four?
If its wide open under the carbs{both carbs feeding front and back}it may be specified on the manufactures web site if the manifold was made with one or the other in mind for a primary.
If its seperate under the carbs ,no progressive linkage will work,both need to be primary and tuned for that use.

Might be a good idea to list exactly which manifold you have and the carb numbers and type.May get more meaningful help with more info.
Heres a search on google for tunning dual quads.
http://www.google.com/search?hl=en&r...+quads&spell=1
Heres a yahoo search...http://search.yahoo.com/bin/search?t...ing+dual+quads.
I would do some reading on this and listen to what has and will be posted.

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Originally Posted by Motown

sorry for al the questions, say for instance if i was running a single 500cfm carb and the jet screw settings were 2 turns out in bolth sides woud i do 1/2 turn on all 4 for the dual quad set up? to equal 2 turns.

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2 turns on each would be the starting point, adjust with a vacuum gauge from there. Denny has an excellent procedure for this, he's the vacuum gauge guy on here!!!!

i really hope that when your saying jets, you arent unscrewing the ones in the metering blocks :EEK:

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Originally Posted by Motown

Thanks, with the vacuum gage how would i get the 18-20 inches , do i go jet to jet till im there raising vacum with each jet or set one side then match the other? and can i hook the guage up to either carb or do i need to hook it up to bloth? thanks again

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The screws are idle mixture screws, not jets. The jets are in the bottom of the carb below the metering rods....

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Originally Posted by Dave Severson

And when it's all done, a good dual plane intake with a single 500 CFM carb will perform the same or better at considerably less cost and headaches!!!! Geez, a lot of $$$$ for eye candy!!!!!

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Hmmm....I'm trying to think of which part isn't "eye candy" and that doesn't cost $$$$

Pat

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Originally Posted by HemiTCoupe

Hmmm....I'm trying to think of which part isn't "eye candy" and that doesn't cost $$$$

Pat

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Yup, you're right..... my point was the "considerably less" part of the money deal.....

Ya I know but I had to say it. ;)

He already put the money out, I have run many 2x4's and 3x2's for many yrs, on a 283 to a blown 454, it is something you will need to learn, you can't bring it to someone every time you think it's off, things change from driving it, and you'll go broke having it looked at, to be something minor, you should have someone set it at 1st, by someone that knows how to, not only says he does. But you need to know how to get it back if something should go out-of-wack.

You can jet them to work( I ran 2 Holley 600's on top a 2x4 tunnel ram on a 283, on the street), you should search this site, theres good info on multi carbs set up, it is mostly about 3x2's, but alot still will help you learn on how they function, and on the chevy forums, and mopar forums, they use a lot of dual 4's

Multi carbs can go from fun to what the hell in no time if something slipped on the linkage. I have stomped the pedal to run someone and nothing! the lock bolt slipped loose. there is more things to keep clean and loose, but not sloppy.

I can fix mine , but it could take me forever to get yours right, without it here to listen to, or look at.

Pat

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Originally Posted by HemiTCoupe

Ya I know but I had to say it. ;)

He already put the money out, I have run many 2x4's and 3x2's for many yrs, on a 283 to a blown 454, it is something you will need to learn, you can't bring it to someone every time you think it's off, things change from driving it, and you'll go broke having it looked at, to be something minor, you should have someone set it at 1st, by someone that knows how to, not only says he does. But you need to know how to get it back if something should go out-of-wack.

You can jet them to work( I ran 2 Holley 600's on top a 2x4 tunnel ram on a 283, on the street), you should search this site, theres good info on multi carbs set up, it is mostly about 3x2's, but alot still will help you learn on how they function, and on the chevy forums, and mopar forums, they use a lot of dual 4's

Multi carbs can go from fun to what the hell in no time if something slipped on the linkage. I have stomped the pedal to run someone and nothing! the lock bolt slipped loose. there is more things to keep clean and loose, but not sloppy.

I can fix mine , but it could take me forever to get yours right, without it here to listen to, or look at.

Pat

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Best tuning tool I've found is a left over from snowmobile racing, a multi-carb balance tube for synchronizing the carbs, one hose from each tube goes to a vacuum port on each carb. The tubes are filled with Mercury (probably illegal nowadays). Just adjust the idle screws til the level in the tubes are even.... As for the linkage, I always run them progressive, nothing fancy required there other then a bit of common sense and a lot of patience!!!! They're fun, but as my years advance and spare time decreases, I'm really starting to enjoy EFI!!!!!:LOL: :LOL: :LOL: :LOL:

Thanks guys, i'm going to try to start tuning these things tommorow. i'm sure ill have some problems so i hope you dont mind the questions..

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Originally Posted by Motown

Thanks guys, i'm going to try to start tuning these things tommorow. i'm sure ill have some problems so i hope you dont mind the questions..

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It just takes a bit of patience and persistence, you'll get it!

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Originally Posted by Dave Severson

Best tuning tool I've found is a left over from snowmobile racing, a multi-carb balance tube for synchronizing the carbs, one hose from each tube goes to a vacuum port on each carb. The tubes are filled with Mercury (probably illegal nowadays). Just adjust the idle screws til the level in the tubes are even.... As for the linkage, I always run them progressive, nothing fancy required there other then a bit of common sense and a lot of patience!!!! They're fun, but as my years advance and spare time decreases, I'm really starting to enjoy EFI!!!!!:LOL: :LOL: :LOL: :LOL:

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I did the same with a tube and water, but now for my Dellorto's carbs on the trike, I bought a synchronizer that I just set on top and adjust the little floating ball to the same place.
I also have been playing with EFI, I converted my Hilborn to electornic injectors. I need a non-working Hilborn fuel pump housing.

Pat

I want to thank every body for there help , i finaly got this thing to run good, i had to change the metering rods to lean it out (edelbrock said to go 6%leaner on my motor combo after they said the first time i called that no adjustment was nesasary)and i used the vacuum guage for the idel mixture screws. I have realy never delt with carberators mutch so i greaty appeiciate the help. you guys are great !!!

Good to hear you have it working! Dual fours do have a "kewl factor" about them! Keep an eye on your plug readings for rich to lean conditions, or maybe find a shop with an air/fuel ratio machine, and see where it's at... If you have quality air and fuel filters installed, the Edelbrock carbs should hold their tune quite well..... Oh yeah, and post us some pics, we all like a little eye candy!!!!!