From the "1966 Comet, Falcon, Fairlane and Mustang Shop Manual", a drawing of the linkage for all 289 CID V-8 engines with an automatic transmission. Included is the drawing for the 200 CID I-6 engines. The 6 cylinder uses a traditional "bell crank" method for the carburetor. It's "complicated". There is an arm welded to the accelerator shaft to control downshifting an AT. Manual transmission cars do not have the arm.
The Shop Manual is another must have document in your library.
Jim