Found it!

http://www.imperialclub.com/Repair/Lit/Master/index.htm

Go most of the way down the page to 1972. It is the "Speed Control and Concealed Headlights" manual.

Some very cool stuff on this site.

Robert

AAR 4-speed 3.91, Tor-Red;
70 440 6 pack Roadrunner 4-speed 3.54, Plum Crazy;
68 Formula S conv 383 4-speed 3.23, Electric Blue;
69 Barracuda conv Slant 6 OD4 2.94, 71 B5 Blue;
78 Lil' Red Truck, Red;
70 Challenger S/E. 505 6 pack, Passon 5-speed, 3.55, B7 Blue