Progressive or 1:1 on Dual Quads?

Posted By: Mopar_Mudder

Progressive or 1:1 on Dual Quads? - 10/14/12 04:14 AM

I had a complete 472 Hemi built and dyno tunned by an engine builder. Starting to put the final pieces on it and notice that the have the progressive linkage set up in a 1:1 configuration. I am wondering pros and cons of both ways and if I should worry about it. I can see where 1:1 might be more dificult to tune, but it was dyno tunned already. But progressive seems like it would run the front cylenders lean at an idle?

Posted By: CrAzYMoPaRGuY

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 05:53 AM

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I had a complete 472 Hemi built and dyno tunned by an engine builder. Starting to put the final pieces on it and notice that the have the progressive linkage set up in a 1:1 configuration. I am wondering pros and cons of both ways and if I should worry about it. I can see where 1:1 might be more dificult to tune, but it was dyno tunned already. But progressive seems like it would run the front cylenders lean at an idle?

I run dual quads on most of my stuff over the last 20 years, even my work truck was 440 2x4bbl.
I don't run progressive linkage, I like running 1:1. I have fancy progressive linkage on my Charger, it's locked out to give 1:1.

I have a CH28 and two Edelbrock 500cfm carbs ready to go on my motorhome, it will be 1:1 too....

Jensen Interceptor drivability with 3.08 gears, stock convertor, and a little blip on the throttle gets a tiny chirp...
http://www.youtube.com/watch?v=NStpPLbRPL4

Posted By: quickd100

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 10:59 AM

I run 1-1 on my tunnelram as well, runs fantastic.Dave

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 01:00 PM

I run progressive. I like it. Run it both ways and see which one you like best. Every motor is different

Posted By: Jack Zupan

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 02:35 PM

I run 1:1 on my 526 hemi and it works great.

Posted By: modelmakerinc

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 03:16 PM

Can someone please expand on the terminology (1:1 & progressive) for those whose might be curious. Thanks

Posted By: Mopar_Mudder

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 03:36 PM

Thanks for all the replys. One less thing to worry about, I will leave it 1:1 and see how it runs, easy enough to change in the future.

Posted By: JohnRR

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 05:11 PM

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Thanks for all the replys. One less thing to worry about, I will leave it 1:1 and see how it runs, easy enough to change in the future.

What intake are you using , that will determine which way you can or want to run ?

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 06:20 PM

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Can someone please expand on the terminology (1:1 & progressive) for those whose might be curious. Thanks

1:1 means that both carbs' throttles are opened the same amount at the same time via a linkage connecting the two. Progressive means the the primary (rear) carburetor is opened first and the secondary one opens sometime after it via a progressive linkage connecting the two. They usually are set up to both hit full throttle at the same time...

Posted By: Mopar_Mudder

Re: Progressive or 1:1 on Dual Quads? - 10/14/12 10:56 PM

It is the repop of the stock Hemi intake, orignal carb spacing dual plane.

Posted By: JohnRR

Re: Progressive or 1:1 on Dual Quads? - 10/15/12 03:15 AM

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It is the repop of the stock Hemi intake, orignal carb spacing dual plane.

You can run progressive with that intake if you choose since it's a dual plane.

Posted By: 62maxwgn

Re: Progressive or 1:1 on Dual Quads? - 10/15/12 03:18 AM

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It is the repop of the stock Hemi intake, orignal carb spacing dual plane.

You can run progressive with that intake if you choose since it's a dual plane.

And you can save a few bucks on fuel !

Posted By: Pyper70

Re: Progressive or 1:1 on Dual Quads? - 10/15/12 10:53 AM

Question for the secondary carb running progressive....should I back the idle circuit all the way out since the engine is running with only the rear one? Should I treat the Two carbs like a double pump Holley and adjust it like 4 corner air bleed screws. Should the rear carb be more lean than the front one? Should they be equal?

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/15/12 01:23 PM

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You can run progressive with that intake if you choose since it's a dual plane.

I didn't realize it made a difference, running dual/single plane with progressive/1:1 linkage. I switched mine (single plane Offy) from progressive to 1:1 yesterday and it is WAY better. Why does it matter?

Posted By: JohnRR

Re: Progressive or 1:1 on Dual Quads? - 10/15/12 02:24 PM

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You can run progressive with that intake if you choose since it's a dual plane.

I didn't realize it made a difference, running dual/single plane with progressive/1:1 linkage. I switched mine (single plane Offy) from progressive to 1:1 yesterday and it is WAY better. Why does it matter?

I would have to see your intake but since the OP has a Hemi there are a few different intakes, if he had a Stage 5 intake he would definitely have to run it 1:1 because it is basically 2 single plane intakes with a small passage that wouldn't feed the opposing 4 cylinders very well, if at all .

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/16/12 10:35 AM

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You can run progressive with that intake if you choose since it's a dual plane.

I didn't realize it made a difference, running dual/single plane with progressive/1:1 linkage. I switched mine (single plane Offy) from progressive to 1:1 yesterday and it is WAY better. Why does it matter?

I would have to see your intake but since the OP has a Hemi there are a few different intakes, if he had a Stage 5 intake he would definitely have to run it 1:1 because it is basically 2 single plane intakes with a small passage that wouldn't feed the opposing 4 cylinders very well, if at all .

It's the same as this one.
http://www.ebay.com/itm/Offenhauser-5206-Dual-Quad-Low-Rise-Intake-Manifold-/310383386977

Posted By: VanishPt

Re: Progressive or 1:1 on Dual Quads? - 10/16/12 11:16 AM

I use 1:1

Posted By: JohnRR

Re: Progressive or 1:1 on Dual Quads? - 10/16/12 03:33 PM

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You can run progressive with that intake if you choose since it's a dual plane.

I didn't realize it made a difference, running dual/single plane with progressive/1:1 linkage. I switched mine (single plane Offy) from progressive to 1:1 yesterday and it is WAY better. Why does it matter?

I would have to see your intake but since the OP has a Hemi there are a few different intakes, if he had a Stage 5 intake he would definitely have to run it 1:1 because it is basically 2 single plane intakes with a small passage that wouldn't feed the opposing 4 cylinders very well, if at all .

It's the same as this one.
http://www.ebay.com/itm/Offenhauser-5206-Dual-Quad-Low-Rise-Intake-Manifold-/310383386977

Bob , on that intake 1:1 would be the better choice for performance because of carb to port layout , running off just one at first would cause the 4 cylinders at the opposite end to not see a decent fuel/air mixture.

You could switch to a smaller set of carbs if you wanted , throttle response would probably improve.

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/16/12 04:19 PM

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You can run progressive with that intake if you choose since it's a dual plane.

I didn't realize it made a difference, running dual/single plane with progressive/1:1 linkage. I switched mine (single plane Offy) from progressive to 1:1 yesterday and it is WAY better. Why does it matter?

I would have to see your intake but since the OP has a Hemi there are a few different intakes, if he had a Stage 5 intake he would definitely have to run it 1:1 because it is basically 2 single plane intakes with a small passage that wouldn't feed the opposing 4 cylinders very well, if at all .

It's the same as this one.
http://www.ebay.com/itm/Offenhauser-5206-Dual-Quad-Low-Rise-Intake-Manifold-/310383386977

Bob , on that intake 1:1 would be the better choice for performance because of carb to port layout , running off just one at first would cause the 4 cylinders at the opposite end to not see a decent fuel/air mixture.

You could switch to a smaller set of carbs if you wanted , throttle response would probably improve.

Ok, thanks

Posted By: Mopar_Mudder

Re: Progressive or 1:1 on Dual Quads? - 10/25/12 04:25 PM

One more quick question. If I am running 1:1 linkage, is their any issue with running the choke only on the back carb? Should the two be linked together? Not that it will really be driven in the cold

Posted By: bobs66440

Re: Progressive or 1:1 on Dual Quads? - 10/25/12 04:29 PM

I have mine on the rear carb only and it works fine. I do have to turn the fast idle down a little though. On the Edelbrock dual-quad kits, it includes the electric choke on the rear carb only.