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Discussion Starter · #1 ·
I'm looking for ideas on making or buying progressive dual carb linkage for inline Holley 600 vac sec carbs. If you have something that works and don't mind sharing please post pics or just make suggestions.
I'm planning on driving to local cruises and shows on one carb. When I pounce on the peddle I want the second carb to open wide.
If you made something that works well please post it.
Thanks everyone.
Mario
 

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I would not go progressive linkage on a Tunnel Ram as they are not made for that. You will have the front or rear carb (depending on which one doesn't come on at partial throttle) that will cause the front or rear cylinders to run lean. The new Edelbrock dual (non-tunnelram) manifold was made to allow progressive linkage as the runners are not long as they are in a Tunnel Ram. I have a tunnel ram on my 383 570 hp in my 1957 Chevy with a 4 speed and I run direct linkage and it works great for cruise nights and car shows! I think you are looking for engine trouble using progressive linkage on a tunnel ram..imho!
 

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Discussion Starter · #3 ·
I would not go progressive linkage on a Tunnel Ram as they are not made for that. You will have the front or rear carb (depending on which one doesn't come on at partial throttle) that will cause the front or rear cylinders to run lean. The new Edelbrock dual (non-tunnelram) manifold was made to allow progressive linkage as the runners are not long as they are in a Tunnel Ram. I have a tunnel ram on my 383 570 hp in my 1957 Chevy with a 4 speed and I run direct linkage and it works great for cruise nights and car shows! I think you are looking for engine trouble using progressive linkage on a tunnel ram..imho!

Ok thanks for the tip. I'm running direct with the coupe right now and its a bit much for the local cruise nights. That's why I thought of using progressive. When needed for open throttle it won't lean out. Maybe I'm asking for too much.
Thanks
Mario
 

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I'd consider progressive if the rear carb is the primary, so it's primaries would be close to center on the tunnel ram. I made up progressive linkage years ago on my '55 Chevy gasser, but don't have pictures. What I did was use heim ends wherever possible, and mine was also set with rear carb as the primary. I hooked it up direct to the pedal rod, and then came off the rear carb with a simultaneously operated rod to the front carb. Put a lock collar on the front rod so I could lock it at a point where I wanted the front carb to begin opening.
By setting the carbs up with a lock collar, I could completely pull the collar off when driving around town, and just let the rod slide through the ferrule on the front carb. Then when headed to the strip I simply slid it down and locked it at partial, or where it opened together with the rear carb. I think this would work perfect with your plan to occasionally drive it to a local cruise, as one carb would be fine for this if it was the rear carb.
 

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Discussion Starter · #5 ·
I'd consider progressive if the rear carb is the primary, so it's primaries would be close to center on the tunnel ram. I made up progressive linkage years ago on my '55 Chevy gasser, but don't have pictures. What I did was use heim ends wherever possible, and mine was also set with rear carb as the primary. I hooked it up direct to the pedal rod, and then came off the rear carb with a simultaneously operated rod to the front carb. Put a lock collar on the front rod so I could lock it at a point where I wanted the front carb to begin opening.
By setting the carbs up with a lock collar, I could completely pull the collar off when driving around town, and just let the rod slide through the ferrule on the front carb. Then when headed to the strip I simply slid it down and locked it at partial, or where it opened together with the rear carb. I think this would work perfect with your plan to occasionally drive it to a local cruise, as one carb would be fine for this if it was the rear carb.
Vall
I like your choice of using the second carb with primaries over the middle section. I can fatten up the mix to keep fuel running to all the cylinders as best as can be with a large open plenum. Leaning towards the back mostly will be experimental. For the minimal amount I will be driving it probably be sufficient enough. And yet she will still have wide open with both. I bet it's going to be a blast. If I can only get more motivated. Thanks for your input.
Mario
 

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Discussion Starter · #6 · (Edited)
I decided to buy this Edelbrock piece. #7094. I think it will work but I'm a ways off from trying it.
We shall see.
Mario
 

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Looks like a spring loaded sliding mechanism. Should be solid, and give some cushion to the 2nd carb opening. That cushion may work well, or may work to hold back on the 2nd carb from completely opening. If it does, you may end up removing the coil spring, and use it without the spring.
I usually make mine up from parts and pieces. I get heims from QS, rod from the hardware store, and throttle arms from Speedway (if needed).
This is the setup I built for the sideways carbs on my Austin's engine:


Both carbs are simultaneous, but one could be made as a secondary by simply putting a slide collar on that carb, and a longer rod, with adjustable lock collar to set where it opened. This simultaneous setup works well, and gets me about 21 mpg on the open highway at 65 mph, with TH350, and 3.73 gears. Wish the Falcon could get even half that mileage!
 

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Discussion Starter · #8 ·
Thanks for the pic and advice Vall.
Mario
 

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Discussion Starter · #9 ·
Well I started installing the Edelbrock progressive linkage and got it to work but the 2nd carb will not open fully. There has to be a bellcrank setup that hits that 2nd carb wide open after the progressive starts to go full throttle. Anyone ever see any kind of setup out there that may do this? I did some searching on the internet but Im getting a lot of false leads and waisting so much time.
 

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On progressive carb setups I've seen, they attached the second carb at a different point on the carb's arm, so it operated quicker than the primary. By hooking your primary to the large hole, and secondary carb to the small hole that's closer to the shaft, you should get full throttle on both.
 
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