Kick down Linkage

[rstockbridge]

I replaced the Holley carb on my 70 RR 383 with a MSD Atomic EFI system. Now I can't get the transmission to downshift when I get on it. I think the problem is the kick down linkage, so does anyone have any idea what the measurements are for the kick down linkage?

 

[miller]

I replaced the Holley carb on my 70 RR 383 with a MSD Atomic EFI system.

Problem isn't the length of your kickdown rod. Still have it?

Probably at the throttle arm. Look at the Holley throttle arm, where the kickdown linkage fit. Measure exactly from that location on the throttle arm, to the pivot point on the arm. That's the 'swing' amount for the kickdown, normally matching the kickdown lever length on the trans itself.

On your MSD unit, probably different length, maybe takes an adapter on the throttle arm, to make it right.

 

[Bruzilla]

The problem is that kickdowns were specifically designed to meet a well-defined geometry, and once you start changing things that geometry no longer matches what the kickdown was designed for and you start having issues. This is why I always recommend that folks go to cable systems when they are making major changes to the top of the engine.

 

[sputnik 440]

rstockbridge and Bruzilla...I find myself also going to a MSD Atomic, maybe a Holley Sniper, to replace a FAST on my 400hp 383, 1973 Plymouth Duster. Rstockbridge, did you find a cure for the kickdown issue? If so, what did you have to do? Are you happy with it? How do you like your Atomic and why did you get it over the other EFIs? Buzilla, not sure how to do cables for a 727. Can you refer me to a good reference on what I need and how to do it?

 

[Fran Blacker]

One don't drive without it you'll burn up your clutches. It's throttle pressure control linkage. The more you push on the gas pedal it increases the hydraulic pressure in the trans.