904 kickdown
I'm not sure-but early slant 6 904's had the part throttle kickdown. I don't remember which ones. A&A Transmission offers a part throttle kit for the 66-70 727's and 904's. The part number is 22740-32si at $95.00. It is money well spent in my book. For anyone having an automatic shift 904 or 727 66-70, this kit makes driving much more enjoyable. I put one in my all original 67 Dart 270 with a 273-2 barrel with 2.71 rear gears and 225/70-15 tires. I can't spin the tires, but running down the Interstate at 80-85 makes up for it. Not having to floor it to get the kickdown, is a lot easier on everything.