I need to start working on the linkage for my dual quads. Could someone take detailed pictures of the setup? I plan on making my own.
Progressive linkage?
- Thread starter Fathead Racing
- Start date
That's a great place to start, looks fairly simple. Thanks a lot.
Solid linkage i built but works and looks great !!!
It`s not hard to make your own progressive linkage using parts from the hardware store and using the stock setup as a blueprint,,,
Edelbrock makes a nice setup http://store.summitracing.com/default.asp?target=partdetail.asp&part=EDL-7094
There`s a better picture of it on the bottom of this page /linkhttp://www.edelbrock.com/automotive/carb_acces.html
It`s not hard to make your own progressive linkage using parts from the hardware store and using the stock setup as a blueprint,,,
Edelbrock makes a nice setup http://store.summitracing.com/default.asp?target=partdetail.asp&part=EDL-7094
There`s a better picture of it on the bottom of this page /linkhttp://www.edelbrock.com/automotive/carb_acces.html
Thanks Jim, I knew I could count on the members to step up 
DQ...how is driveability with solid non progressive ?
Since dq is not yet awake, I will slip in my opinion. A perfect subject for the first major "differance of opinion" controversey of the new year. IMO , it takes a given amount of air-fuel mixture to perform a particular job. Example:: Imagine a car with 409-2 4s. Smooth acceleration from standing start to 50 mph. It doesnt matter which linkage is used, if rate of acceleration is the same, it would take the same amount of air-fuel . With progressive, you would be using much more of the rear carb. than the front, to acheive the job. With direct , you would use just enough of the primaries of each carb to perform the job. Remember, rate of acceleration must be the same. Why does direct linkage get poorer milage? It has nothing to do with the linkage, it has everything to do with the driver. The direct linkage has a quicker throttle response, low speed acceleration is quicker and crisper. That is the drivers choice!! You cant help yourself with direct linkage, to rap the gas pedal more when at an idle. You cant help accelerating quicker when doing the everyday driving. Its fun the way the car reacts with the two sets of primaries hooked together, at lower speeds. But if you could restrain yourself, and keep rate of acceleration the same as progressive set-up, then fuel milage would be the same, because, once again, it takes the same amount of fuel-air mixture to do the same job, no matter which linkage you use. So I guess my opinion is that technicallly , both types of linkage delver the same gas milage, but direct linkage has a bigger fuel usage factor, thus costing more at the pumps. Again , this is only an opinion, I have no tests, facts, or any data to support this opinion. Happy New Year to all!!!!!!!!
Direct linkage
Ronnie, you hit the nail on the head with that response. Keeping the foot out of the carbs is the deciding factor. And, that is really tough to do. They are very responsive with the direct hook up. If jetted right. And a set of ears that used to hear them really rap up quick, doesn't forget. When it's available, ya just gotta hear it again, and again, and again. Fuel cost goes up. But, gee it's fun.
Ronnie, you hit the nail on the head with that response. Keeping the foot out of the carbs is the deciding factor. And, that is really tough to do. They are very responsive with the direct hook up. If jetted right. And a set of ears that used to hear them really rap up quick, doesn't forget. When it's available, ya just gotta hear it again, and again, and again. Fuel cost goes up. But, gee it's fun.
Geeezzzz Ronnie,,, I`m gonna sleep in longer from now on !!
Thats a great explanation on the differences of the two styles of linkage (drivers too) !!
I think the only thing I would add is maybe the drivers that get better mileage with progressive are running a bit lean.
My car drive just as you have stated and I think my setup has a cleaner look.
Gas mileage ?????
I don`t think you own a big heavy classic car with a high compression, big cammed, dual quad carbed, large displacment engine and think your gonna pass a gas station !!!!
Thats a great explanation on the differences of the two styles of linkage (drivers too) !!
I think the only thing I would add is maybe the drivers that get better mileage with progressive are running a bit lean.
My car drive just as you have stated and I think my setup has a cleaner look.
Gas mileage ?????
I don`t think you own a big heavy classic car with a high compression, big cammed, dual quad carbed, large displacment engine and think your gonna pass a gas station !!!!
I have to run direct set up,because the cross ram,1 carb feeds 1 bank 
.But I was surprized at my fuel mileage to Norwalk was 11 MPG with 3:50 gears 
.But I was surprized at my fuel mileage to Norwalk was 11 MPG with 3:50 gears 
fuel economy
I ran my 474 dual 600 edelbrocks and 336 gears with the straight linkage last year and got 13 mpg. I was not driving easy and even did a few smokey burn outs. I tried progressive linkage, but like the solid. Seems more responsive to me. Sure can't wait for spring time.
I ran my 474 dual 600 edelbrocks and 336 gears with the straight linkage last year and got 13 mpg. I was not driving easy and even did a few smokey burn outs. I tried progressive linkage, but like the solid. Seems more responsive to me. Sure can't wait for spring time.
That works great but only for one thing, accelerator pump shot! True, if you are cruising it only takes so much fuel air to maintain a given speed. Where the fuel savings are in the fact that you are not in a stop and go situation! We all know that when the manufactuer gives gas mileage figures it is city and highway! No way are you going to get the same mile per gallon with the linkage hooked solid compaired to progressive linkage. You can't have your cake and eat it too! You would be surprised at how much fuel is used every time you mash the throttle.
"You cant have your cake and eat it too." You are sure right about that, Ray! You cant drive a 409 in a 4,000 lb. car and get good gas milage, no matter how much or how little the 2nd accelerator pump squirts. Its all about the fun factor. If you give the direct linkage a try, after you hang the 690s on, I bet you dont go back to progressive. If its gas money you need, please sell me your wifes Caddy, I sure would like to have that car. 
Yeh Ronnie I know what you mean. I think at the strip I will run the linkage solid, but on the street progressive linkage is for me.
fatride said:Yeh Ronnie I know what you mean. I think at the strip I will run the linkage solid, but on the street progressive linkage is for me.
Then spend the money for the Edelbrock set-up and do a little clean up on the TOO big blocks and you can have it both ways.
With their set-up and most any progressive set-up you can slide the stop to where ever or how fast you want the second carb to come in.
This can also be used to tune out a bog on launch,,, but I prefer to get that bog out by tuning the secondaries on them wonderfull AVS`s !!
Paul? Either way Ray I`d bet you wouldn`t know the difference in gas mileage,,dq
Pump shot
Either one or two accelerator pumps pumping will have minimal to no effect on fuel economy assuming you are getting the correct amount of fuel per pump. If carbs are tuned properly, the engine will run properly both ways. How many pump shots per gallon anyways? If you look at it like that, seems kind of fuelish. ( pun IS intended ) You will notice quite a bit more acceleration with the straight set up. You seem to be after performance, and straight linkage is all about that. You will have a hard time switching from progressive linkage to straight linkage and not have to perform any adjustments. When I changed I had to adjust pump shot, timing and I believe jetting to get it to run its best. I hope you come to the proper conclusion. I did.
bang
Either one or two accelerator pumps pumping will have minimal to no effect on fuel economy assuming you are getting the correct amount of fuel per pump. If carbs are tuned properly, the engine will run properly both ways. How many pump shots per gallon anyways? If you look at it like that, seems kind of fuelish. ( pun IS intended ) You will notice quite a bit more acceleration with the straight set up. You seem to be after performance, and straight linkage is all about that. You will have a hard time switching from progressive linkage to straight linkage and not have to perform any adjustments. When I changed I had to adjust pump shot, timing and I believe jetting to get it to run its best. I hope you come to the proper conclusion. I did.
bang
Food for thought....... 409 2-4bbl car. Staged and ready for lights to come down. Manual shift car, gas pedal depressed for 3,000 to 4,000 rpms launch. or A/T car , gas pedal depressed to just short of stall (2000rpm) . Launch time, stomp gas pedal to floor. Which linkage is best for launch? Answer is -- either!!! Either linkage will produce 8 bbls WOT instantly. The differance inthe two would be measured in thousandths of a sec. No differance when mechanics of the car (suspension, etc.) are taken into consideration. Those who prefer progressive linkage need not change just for drag racing. The only differance in the two is the fun factor. And also if you look at the front carb activity during normal city driving with progressive linkage you will be surprised at how much the front primaries are used. To keep front carb. from being used in normal driving , you would have to creep everywhere you go. AS said before , this is just food for thought. How long does it take to stomp gas pedal to floor,(especially when it is already at half throttle)? The blink on an eye. Maybe .010 of a sec. I think less.
I'm not walking to this blind. I have progressive linkage with my three two setup now. I can get away from the stoplight with traffic and cruise at 80 mph without getting into the secondaries. I think it will be progressive linkage for the Fatride! I flash the converter at the strip with a 1.89 60'
Well I`ll be the first one here to say that the three - two`s is a completely different comparison,,IMO,,,
Some how the three-two`s act differently as in the statement you made Ray.
In my limited experence with the two setups I would bet that the three-two`s would be the more efficient setup for the street as they work like you said and the primary carb is used until you really nail it.
Back to what Ronnie said when I was still asleep
: I think is the best senario for the Dual Quads,,,,
Ray ,,If you want any kind of mileage other then what a DQ will give you, stick with the three two`s,,,,
I`d bet that after a short while with the dq`s you`ll have sold linkage !!! ,,dq
Some how the three-two`s act differently as in the statement you made Ray.
In my limited experence with the two setups I would bet that the three-two`s would be the more efficient setup for the street as they work like you said and the primary carb is used until you really nail it.
Back to what Ronnie said when I was still asleep
: I think is the best senario for the Dual Quads,,,,Ray ,,If you want any kind of mileage other then what a DQ will give you, stick with the three two`s,,,,
I`d bet that after a short while with the dq`s you`ll have sold linkage !!!
,,dq