I thought I had lost my kickdown linkage while my car was apart.. Stock 67 440/727..
Looking at my FSM, looked like the 383 was different AND the small block different also..
I had some stock Kickdown linkages from some parts cars, so I thought I was OK..
Fortunately I found the correct linkage off of my car... What I can tell you is the lengths, belcranks, and rods are slightly different between all three of the above motors.. So the Service manual is correct that each linkage is ever so slightly different...
SOO, when you look for the correct kickdown linkage they can be very close but not correct depending on the application...