I found a stash of my old ancient club newsletters from years past(1990)- and there are some tech tips relayed from early Ford service bulletins from 1965-66 I thought I'd throw out there for what they are worth before I throw away the old newsletters:

-Wind Whistle/Noise 1965 Mustangs:
Wind Whistle and/or noise has been experienced on some 1965 Mustangs when the tie rod adjusting sleeve slots are facing forward into the air stream.
This noise occurs at 30-40mph. When a customer complains of a wind whistle or noise underneath the vehicle, the tie rod sleeves should be inspected for slot positioning. If the slots are facing Forward they should be filled with body sealer or any caulking that will not wash away.

Driveshaft Balancing 65-66 Mustangs (Except 6-cyl):
Complaints of excessive driveline vibration at certain driving speeds have been received regarding 1965 and 1966 Mustangs. It has been found, that in many cases, these vibrations have been caused by inadvertent matching of the maximum out of balance conditions of the driveshaft and rear axles universal joint companion flange. To correct this problem in production, the light side of a driveshaft runout condition and the maximum runout condition of the universal joint companion flange have been identified with a daub of yellow paint. matching the daub of yellow paint on the driveshaft, with the daub on the companion flange, will allow maximum balance condition possible to reduce driveline vibration complaints to a minimum.

Hey Paul got any more tips. They are really quite helpful. Especially the tailshaft. I would never hear the wind noise as I Can't even hear the radio over the v8 rumble .Thats music enough.
Norm

That was just a couple from some old, old club newsletters I had but I'll try to keep an eye out or come up with some more