When I swaped my I6 for the V8 thats in it now the first brackets and monts I got were 66 stuff I believe tryed to put the motor in and it just would not sit right. I went back to the place I got the stuff from they told me to try the 65 brackets and monts which they of sold me put those in and the motor just droped right in with no problems. heres a pic if it helps

[IMG]local://upfiles/33399/F444C288C2A1459AA3969CF9284BE1B3.jpg[/IMG]

 

He put in some aftermarket type of mounts. They look universal and should fit even though the info on the page he refered to missed some yearapplications. I upgraded my 66 hardtop engine mounts from the 65 style the car came with from the factory, to 68 mounts without a hitch. The mounting holes in the frame are the same for all 64 thru 66 Mustangs - except if they got distorted from an accident.
Jim