Reverse Valve Body???

Well the 72' Duster I just bought. Has a 727 with 4200 converter and manual reverse valve body. (the one in my avatar) You want the manual valve body cause it shifts when you want it to shift (and Hard) This is usually used with a "slap or ratchet" shifter. Every time you slap it , goes up one gear. When you get to a stop light you have to "ratchet" it 3 clicks back to 1st. Hence the name. Think of a manual tranny that shifts just by pulling the lever, no clutch pedal involved , just pull the lever for every shift. I'd be inclined to say that you'd only want this setup for more of a race car than a daily driver.