This is airmanship. The energy management required for that maneuver in a Shrike is exceptional.
Bob may have sanitized his narrative in that clip a little for public consumption. The story I got from my retired Air Force primary instructor who knew Bob was that the trick used to be done by setting a shot of whisky on the top of the panel, but the FAA raised hell about it (may have been the CAA back then). Hoover had his airman's medical taken away by the FAA without cause because, well, the FAA does things because they can, not because they should. It was ultimately reinstated.
The primary reason you don't remember Hoover is that he was a victim of bureaucratic power.
Bob may have sanitized his narrative in that clip a little for public consumption. The story I got from my retired Air Force primary instructor who knew Bob was that the trick used to be done by setting a shot of whisky on the top of the panel, but the FAA raised hell about it (may have been the CAA back then). Hoover had his airman's medical taken away by the FAA without cause because, well, the FAA does things because they can, not because they should. It was ultimately reinstated.
The primary reason you don't remember Hoover is that he was a victim of bureaucratic power.