Supercuda -- "The E bodies had clearance issues and the engineers found that using the shorter idler made the needed clearance and the change in L vs R ratio was small enough not to matter."

I find that hard to believe as there are no "clearance issues" with a factory setup, nor with the longer idler arm with a factory exhaust. I personally spoke with Chrysler engineers about this matter in the mid-70s.. They knew about it right away, but by the time it could be corrected by having to change the standard short factory idler arm to the longer and correct C-Body idler arm, whenever the Fast-Ratio power steering box was optioned for the car, it was too late in the production runs... and the overall cost factor was an issue. Furthermore, not that many cars were being ordered with the "Fast-Ratio ps option". The writing was already on the wall to kill the AAR/T/A and the Fast-Ratio ps option -- even for the early 71 E-bodies having that option made available... which hardly anyone, including the dealers, knew about. So, it was decided to move on and leave it alone... marketing the ps option as "Fast-Ratio" was cool and attractive, and needed at that time; too bad they screwed up. Bottom line: It would've been too costly to make that needed production line change.

Shame on MaMopar for ignoring the matter.

Also, remember, no-one "created" or "developed" what has become known and referred to as the "fast-ratio idler arm"... it is simply a ~70 C-body idler arm.