Is there any other rear that will work in my '65 barracuda??????

8 1/4 works fine. If you get desperate a ford 8" will work. Tons of old Mavericks, Comets had them. I would stick with the Mother Mopars's 8 1/4. I am in the same boat as you $$ and I am considering one. Still would love to have the 8 3/4 though . this is the first car Ive had without one. 68 RRunner, 64 Fury, 70 Duster all had 489 cased 8 3/4 rears...........ahh those were the days.