I have never owned a Model A that had or has a shortened pitman arm. I buy arms from the dealers that are built shorter. Have had no issues with any of the cars I have installed these on. As is pointed out, the stops come into play so the steering radius remain the same. I use the 1956 Ford pickup box and make sure it is in spects or rebuild it to spects before installing, With the two, the shorter arm and the 56 box the roadster is much like power steering. Heavier cars were also vastly improved, for me. Your results may vary.