Ignition Issues - Car Won't Start Intermittently

67Dart, I own a service manual and the first thing I tried was attempting to adjust that external linkage. I watched as my neighbor shifted the car from park to drive and back again to determine which was it'd need to adjust. Then I loosened the bolt and attempted to adjust the linkage. It was tight, I could not manipulate it any further. That's what led me to thinking it was something in the wiring either between my tumbler, starter relay, NSS, etc. The car is in great condition and the external linkage is no different, it looks solid, I don't THINK the problem is in the linkage.