Most of the larger Mustang parts sites sell them. I think I got mine (65 Falcon, Fairlane & Mustang shop Manual) from Musthangs Unlimited.
Good luck with your re-build!
1965 Convertible 200 I-6, C-4 Auto, Long Console, 6K Rally Pac, Power Top
1969 Mach 1 351 (W) 3-Speed Manual, Winter Blue, Deluxe Interior, All original.