I have been converting my fleet of ADs with the later sending units which have the fuel pickup as a part of it. They bolt right in and the fuel is picked up just above the bottom of the tank and has sock on the end of the pickup tube. This prevents blockage from debris sloshing around the bottom of the tank from clogging the fuel outlet.
The on again/off again blockage from debris with the original setup makes troubleshooting a nightmare.
Carl
