A potential problem with Super Sixing my 1973 Duster.

Yes, I will get all the parts of the kickdown linkage, throttle cable, etc. Even the exhaust manifold and its choke assembly.

But what's this about the transmission kickdown lever being different?

Longer or shorter lever? I never heard that before, although I did have a 20 year gap of no Slant 6 vehicles, 7/2004 - 7/2024. I had always set up my kickdown linkage to be pushed fully rearwards at wide open throttle. Never blew up a 904, but I did break 6 7-1/4" axles in about 11 years in various ways (wheel bearing, differential spiders, ring and pinion gear teeth, etc) with my constant hard accelerations!
I think they are shorter, I am unsure, but they are different. If it's there, get the thing.