Using 318 Kick Down LInkage with a 340 manifold and Thermo Quad?

[Dibbons]

I would rather not use the Lokar-style kick down setup. I prefer to re-use the factory 318 kick down linkage because I just like the way its setup (photo #1).

I transferred all the '72 318 linkage to '72/'73 340 intake manifold and that is fine. However, the Thermoquad doesn't exactly match the Carter BBD .So for this week, I made an adaptor for the Carter to fit on the 340 manifold just for fun to see how it runs and shifts (initial start-up coming soon).

I did purchase some kind of bracket (see photo #2) that is supposed to be for a 340 but looking at it I can't even figure out how the 340 used it, let alone how I can use it or adapt it for my purpose.

Maybe I'm mistaken, but I would think someone out there in Mopar land would have done the same thing I'm trying and will chime in. Thank you.

 

[Kern Dog]

As long as the Throttle Valve linkage on both the transmission and carburetor reach WOT at the same point, I don't see a problem. I've cobbled together linkage for many 4 barrel conversions. Heck...I don't even know what a correct 4 barrel linkage looks like.
I have never burned up a transmission from misadjusted linkage.

 

[1 Wild R/T]

Back in the 80's & 90's, maybe even early 2000's finding complete small block 4bbl Aspens & Volare's was pretty easy, they used a variation of the three piece style kick down linkage....

I used those parts on dozens of cars that I converted to 4bbl manifolds...

Most other body styles with a small block & a 4bbl used the one piece style linkage which doesn't fit as well or work as consistently...

These days parts are harder to find so if I were doing a conversion I would use the 2bbl parts but my welder & grinder would be getting more experience...

 

[Kern Dog]

From the intake down to the transmission KD lever, I figure that the setups are the same. Up top, I've extended the linkage rods, modified the mounting brackets and just made stuff work.

 

[Geoff 2]

On a 4 bbl carb [ TQ ], the primary throttle shaft is probably going to be further forward than with a 2 bbl carb. T/cable & k/down connect to this shaft. I am not sure how Chrys handled this difference, but it could have been with a different t/cable & k/down parts/levers.

 

[1 Wild R/T]

From the intake down to the transmission KD lever, I figure that the setups are the same. Up top, I've extended the linkage rods, modified the mounting brackets and just made stuff work.

The intermediate rod (from bell crank to bell crank) is about 1/2" longer on a 4bbl set-up due to the taller manifold... That's where that redesigned throttle cable/KD bracket comes in, it cheats the position of the KD pivot to find a spot where the shorter rod can work.... It's better to lengthen the intermediate rod...

 

[Kern Dog]

Since I have seen so few actual 4 barrel LA series linkages, I've just modified stuff to fit and work. Maybe I've just been lucky?
It wouldn't be unusual. I've had good luck most of my life, skirting disaster that others hit head on, it is like I have a guardian angel or something.

 

[1 Wild R/T]

On a 4 bbl carb [ TQ ], the primary throttle shaft is probably going to be further forward than with a 2 bbl carb. T/cable & k/down connect to this shaft. I am not sure how Chrys handled this difference, but it could have been with a different t/cable & k/down parts/levers.

There's a 727 trans lever and a 904 trans lever... There are assorted bell cranks with different ratios & angles but generally if you keep the original lever & bell cranks the ratio will work.. The sweep at the carb stud originally remains consistent whether 2bbl or 4bbl... Where the issue comes from is guys bolting a stud onto the throttle lever in whatever hole they can adapt to.. Holley & Carter both sell add on levers with the proper Mopar lever ratio..

 

[1 Wild R/T]

Since I have seen so few actual 4 barrel LA series linkages, I've just modified stuff to fit and work. Maybe I've just been lucky?
It wouldn't be unusual. I've had good luck most of my life, skirting disaster that others hit head on, it is like I have a guardian angel or something.

Never argue with luck or angels...

 

[Darter6]

Just a few photos of small block 2 bbl linkage hooked to 4 bbl

 

[Dibbons]

Just a few photos of small block 2 bbl linkage hooked to 4 bbl

Looks like a little ingenious custom fabricating took place.

View attachment 1909281

View attachment 1909280

 

[Darter6]

Yeah, the second photo, I'm not proud of the throttle cable but sometimes you use what ya got.
Crappy aftermarket but it works.
The manifold bracket is 2 bbl. Just needed a little bending for alignment. Hardware store threaded long nut and all is good.On both cars.