67DodgeDart360
Well-Known Member
I am running A 2 barrel kickdown bracket and linkage.
Is the kickdown linkage set up right?
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pearljam724
Well-Known Member
2 barrel kickdown linkage isn’t the issue. A 2 barrel linkage works just as well as a 4 barrel linkage. If you add an extension made from all thread. As I suggested earlier. That’s your problem. That and your springs are entirely too heavy. You need to buy actual carburetor return springs. They are universal and many are available on ebay, etc. The bolt you added to the yoke slot screws up the travel of the kickdown linkage as well. In that position the kickdown linkage travel is not set up correctly. If you add an extension as I suggested. It will correct the travel of the kickdown linkage. The way you have it set up wth that bolt. It’s engaging entirely too soon. That effects the correct pump pressures shifting from one gear to the next. Kickdown as well. Ditch that bolt and add an extension. It will work, if you do this.
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67DodgeDart360
Well-Known Member
Ok thanks, will these work? https://www.autozone.com/interior/u...iwyh-EOdMiy1V3bfegEaAhOdEALw_wcB&gclsrc=aw.ds
pearljam724
Well-Known Member
Give me a minute. I ll post better options.
pearljam724
Well-Known Member
These will be better options. You need 2-3 of these types of springs. 2 will get the job done. It won’t hurt to buy the Autozone springs too. If you end up using one from a $6 kit great. If not, return them. The ones you are using now are ridiculously too heavy. For Mopar Dual CARBURETOR RETURN SPRINGS 340 440 383 Plymouth Dodge A, B, E-body | eBay
OK, Edelbrock carburetors use a special Mopar throttle bracket so that things line up properly with the throttle cable and kickdown linkage as pictured below:
Now, you need the Holley carburetor throttle linkage adapter for your Holley setup on your mopar. This will give you a better swing on your throttle cable/kickdown linkage so the geometry is right.
When you step on the throttle it will give you full power, unlike the setup you have now where it will not swing the throttle open all the way because the geometry is wrong.
Then you can also get the throttle cable and kickdown linkage on the same axis for the swing of the carb lever, both working together.
You need the full power going to the transmission if you want the transmission to kick down when you step on the gas.
Now, you need the Holley carburetor throttle linkage adapter for your Holley setup on your mopar. This will give you a better swing on your throttle cable/kickdown linkage so the geometry is right.
When you step on the throttle it will give you full power, unlike the setup you have now where it will not swing the throttle open all the way because the geometry is wrong.
Then you can also get the throttle cable and kickdown linkage on the same axis for the swing of the carb lever, both working together.
You need the full power going to the transmission if you want the transmission to kick down when you step on the gas.
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pearljam724
Well-Known Member
I agree that bracket is a must.
67DodgeDart360
Well-Known Member
Thank you so much everyone for all the information. I purchased the Holley carburetor throttle linkage adapter and the springs.
67DodgeDart360
Well-Known Member
And should I purchase a Throttle bracket too? I was looking for something like this.
pearljam724
Well-Known Member
No, you don’t need it. The bracket you have will work fine. You need to go to a hardware store and buy a piece of all thread and a coupling nut the same thread size as the end of the linkage that the clevis screws on to. I can’t remember how long the extension needs to be. But, if memory serves me correctly it’s between 2.5 to 3 inches. You couple that extension piece on to the end of the kickdown linkage with a coupling nut. You can’t see the extension in my picture because it’s inside the coupling nut and clevis, because it’s so short. The linkage only needs to extend a couple inches. I can’t remember thread size, but it’s fine thread. All you have to do is take a nut that spins onto the end of the rod to a hardware store and say. “ Hey give me a short piece of all thread the same thread as this nut” You take that piece home and cut it the correct length that allows the yoke to extend to the stem on the carb. All you have to do is mimic my picture. It doesn’t get any simpler. Home Depot and Lowe’s won’t have it because of a fine thread. You have to go to a good hardware store. That specializes in odd stuff. Or give me your address. I have a piece left over. I can mail it to you. That’s all you need to do, to make everything work properly.
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You can modify a two barrel throttle bracket to work, but if you have the money (less than $40), this will make it easier:
MOPAR 1968-73 340 Small Block Throttle Cable Bracket 4-Barrel Dart Duster Cuda | eBay
You'll still need to lengthen the kickdown rod, but that's not too difficult. See above.
MOPAR 1968-73 340 Small Block Throttle Cable Bracket 4-Barrel Dart Duster Cuda | eBay
You'll still need to lengthen the kickdown rod, but that's not too difficult. See above.
And at some point, switching to a real four barrel intake will give you more power than your two barrel intake/adapter. Last time I checked, you could by a used Performer for less than $100.
pearljam724
Well-Known Member
All thread and a coupling nut cost a few bucks. There’s no need to buy stuff that people set out to make money on. When you can make what you have work for a few bucks. No need to spend 50 or 60 dollars on other unnecessary brackets. You don’t need. 2 or 4 barrel linkages and brackets work the same on any set up. The only importance is the yoke clevis is pulled up against the carb bolt /stem at idle by spring tension. In order to accomplish this. You need to add an extension made from all thread on a 2 barrel kickdown linkage. Not hard, to figure out. Coupling nut pictured.
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The big difference in hieght is due to the intake. So its not so much 4 bbl vs 2 bbl. When using a lower single plane like a street dominator the '2bbl' setup is pretty good.
Changing the geometry of the adjustable link to the upper bellcrank changes the distance it moves the other two rods.
Oldmanmopar just posted bunch of good photos and description in the post about throttle cables in the Fuel subforum
Changing the geometry of the adjustable link to the upper bellcrank changes the distance it moves the other two rods.
Oldmanmopar just posted bunch of good photos and description in the post about throttle cables in the Fuel subforum
pearljam724
Well-Known Member
With a coupling nut. You can adjust the length of the rod to any length you want. Lengthening the rod over comes any geometry issue. No need to complicate the fact by adding in other irrelevant points about brackets, intakes, carbs, etc. None of this matters. Lengthening the rod fixes all of this. It’s that simple.
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Not really. Bellcranks are sensitive to geometry.
Whether you beleive (or not) that it makes any significant difference in the transmission's throttle pressure, is another story. I'll go by my experiences and you can go by yours as far as that goes.
Let's look at the geometry and then anyone who is interested can see how changes in position can effect the relative distances moved.
Here's a sketch of three links with first and third horizontal, connected by two bell cranks.
We can call position 1 closed throttle, and the other two half throttle and full throttle respectively.
If everything was drawn perfect (its not) the distance travelled by the the first pin would be the same as the distance travelled at the last pin.
Now what happens when the geometries are changed?
Here's one example to illustrate.
Here's an extremely shortened intermediate rod.
Yes, extreme - because its easier to see.
The throttle rod is kept the same, and the lower rod has been rotated with the bellcrank.
67DodgeDart360
Well-Known Member
The bracket I had was too short. I think I need something taller. Thats
should I purchased a different intake? And what one you recommend? And should I purchase this set up? For MOPAR Small Block High Rise Intake THROTTLE BRACKET Kit 340 360 318 Dodge + | eBay
That slotted kickdown lever needs adjusted tighter to the throttle stud. (I know it's not in the car yet) LOL
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