Hi Mark - missed your post a few days ago - I had to build a positive stop on my outfit. The diagram I drew (above) shows where I finally ended up placing the stop on the back ledge of the block. A stack of washers adjusts it. The internal throttle return spring of the later Holley carb causes an imbalance among all of the "spring loads" - it is a lot stiffer than the original carb. You should be able to push down on the foot pedal and open the carb to full throttle (first) - then the linkage begins to move the kickdown lever in its slot to make the kickdown rod move down. You usually have to experiment with more spring on the kickdown to get the sequencing right. Once the sequence works - you adjust the kickdown rod so that it is raising the transmission pressure.
On the Holley 4160 carb I first fitted on there, I had to drill a new hole in the throttle lever to get the arc of motion reduced to match the linkage travel of the teapot. Otherwise, it required too much movement of the foot feed - and I didn't have anything left to operate the kickdown. I got the ball stud, socket and link rod parts from Speedway in Nebraska.  

 
 Steve Metzger       Tucson, Arizona

I am trying to figure out what is wrong or missing a Part possibly on the Bellcrank on the 56 I purchased recently. The vertical Throttle return Spring from the bracket next to the Distributor up to the Lever does not have anything to stop the Lever from going down raising the Link to the Carburetor until its almost strait opposite the Carb Throttle Hookup.What is supposed to stop the return Spring from pulling down too far? This also raises the Pressure Rod down to the Transmission Control Valve hookup far higher than it should be making the Rod longer than it should be. Looking at the same Setup on my other 56 I don't see anything missing but maybe there is. Just not seeing it. If I simply disconnect that return Spring and use an external universal return Spring,  Connection Points for the Link to Carb and and the Transmission Pressure Rod will Lineup the same as my other 56. Ad the vertical Spring and both Connection Points are too High because the Spring retracts too far. Is that vertical Spring a return Spring only or does it affect the operation of the Detent assembly. Both the other Springs for the Kickdown are in Place and not missing..
I have just installed a "B" Manifold, 390 Holley and late Distributor. Just trying to get the Linkage to work with this Setup.

  

I made this drawing years ago for YBF - and it looks like it has made the rounds......it is specific to the Fordo linkage on the T-bird - but it does show the nuances of trying to make this stuff work. You need both the car manual - and the manual for the Ford-O-Matic to get all of the instructions - they don't appear together for some reason (in the FACTORY literature).

The pedal height off the floor must have sufficient travel to (1) pull the carb primary to the full open throttle position and then (2) continue on to pull the kick-down lever to its full travel position in the slot. Due to the use of aftermarket carbs (I've used both the Holley 4160 and the Road Demon Jr. four barrel)  both of them have had a very strong internal throttle return springs - the kick-down spring gets overpowered and moves too early. Try the T-return spring in a teapot and you will see what I mean - very light spring - carb goes wide open before the kick-down moves. Some have told me they simply use two kick-down springs to balance out the newer carbs.
There is a lot of monkey motion in the linkage, so I decided that to get the foot pedal to always start from the same position, the outfit needed a positive stop. I use a stack of washers under a bolt at the back of the intake manifold to stop the bellcrank when the pedal height is correct. That makes everything return to a known point when you release the pedal.

This photo shows the use of a Philips screwdriver as an alignment tool - as explained in the factory manual - to get the linkage adjusted at idle. The throttle pedal is released, a foot solid on the brake - and the carb at hot idle with the trans in gear (my wife usually does the brake holding). With the screwdriver in place, the threaded carb linkages get adjusted to fit into this position. Remove the screwdriver - and nothing should change.  

On the near side of the photo - just above the screwdriver handle - you can see the pin that drives the kick-down rod (which is missing in the picture)
.
I don't have a way to show this, but the kick-down rod drops down to a lever on the transmission - where it operates a pressure valve internal to the transmission. As the kick-down rod is actuated, the pressure rises and eventually - it raises the control pressure sufficiently to cause the downshift. The Fordo manual actually has a pressure reading - and a point to check it - when actuation takes place. 




 
 Steve Metzger       Tucson, Arizona

You didn't state whether you had an automatic trans or a manual one.  The picture shown above is for an automatic.  The manual trans may be different.  There are two springs (as shown in the picture), one vertical and one horizontal (the horizontal controls the down shift rod if I remember correctly while the vertical one provides the return of the linkage.

Both springs should be available from the parts suppliers.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I don't think you should need another spring the Holley has its own and with the bell crank springs it should all be fine.



"Came too close to dying to stop living now!"

This section from HAMB has a decent explanation.   Hamb kickdown info


Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

can you post pictures of your spring setup?

The vertical spring, and I hope you still have the original one, is more of a downshift control. I use a regular double spring on the carb connection for throttle return. If you don't have the right vertical spring its nearly impossible to get the kick down to work correctly. (found out the hard way).


Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

About to install my rebuilt Holley 4160(1848-1) carb on my 1956 Crown with 292 CI-v8. I have been using various Holley carb videos on youtube to help with the rebuilding and installation. On may of the videos, a throttle return spring - sometimes a double return spring is installed from the carb throttle linkage to a fixed point around the bell crank area is used to return throttle to the idle position. I only have an accelerator return spring located vertically along the firewall on my setup.
Do I need to install a separate throttle return spring in addition to the accelerator return spring? How was it designed from the factory?

Thanks
Danny