I just did it on my 66 this year. Rev gives some excellent advice. Another tip someone gave me (AFTER !!! ARRRRGGHHH!) was to put all the screws in (i.e. for the visors, mirror, coat hanger, etc..)when the headliner is out, and screw them all the way in . This way you can easily locate the holes and cut the headliner where the phillips x is in the screw, remove the screw, and put in the item (i.e. visor). Also, you may want to have a heat gun handy. By heating the healiner it makes it easier to stretch. I read 3 books on this before I did it and these tips would have helped.
The most important thing to remember is PATIENCE, PATIENCE, PATIENCE
Good Luck !
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347, 279/284 .493/.510, TFS TW, Stealth, 750, Flowtech hdrs, Dr. Gas X, 2 Chmbr Flowmaster, MSD 6AL-Dist.& SS coil, Art Carr C-4, Currie 9" w/3.55, alum Drv Shft, susp mods, 4 wheel power disc
In a 66 coupe