The Scott Fuller diagram I shared earlier (
http://www.scottfullerreproductions.com/1968MustangGT390.html )
is how I would expect to see a 68 GT 390 Mustang tail spout quad tip. Click on the links to the individual parts he sells within the 390 Mustang link to get a good look at original vs. his reproduction parts. He generally does a side-by-side of the reproduction next to the best original examples he has available.
I understand the quad tips are made to order (by Fuller) but a majority of the other items of any system are readily available to ship.
Also, Scott Drake (not Fuller) sells a decent reproduction Quad Tip but DRAKES do not have the engineering numbers stamped into them.
The tips used on the 1968 390 Mustang, were
clamped on with the horseshoe-looking clamp originally throughout the year (or so I always believed). The tailpipe would typically be attached to the "J" tailpipe hanger with a band-style strap clamp (Fuller also sells the best reproduction of BOTH of these types of clamps.) Other vendors such as NPD, sell the hangers and clamps with the O.E. Ford markings (at or around the same price as Fullers) but to my knowledge, only Fuller sells his O.E. Exact pipes and mufflers.
These statements in this reply, are as true to my knowledge as possible. I am always willing to learn I am incorrect but unless we have any other documentation as proof, I would follow Fullers 390 Diagram as a basis of at least a "parts list" of what you should be hunting.
PS: Also look at Fuller's "Mustang Parts For Sale" page for additional hangers and hardware.
http://www.scottfullerreproductions.com/page/page/4595229.htm
