My first car was a 65 Mustang with K motor (289 hi-pro). My dad bought that one and a 66 with a GT package for my tow sisters. I bought the 65 from my sister in 1977 and it shipped back from Hawaii where she lived with her husband while stationed in the army.
When they opened the shipping container on the dock in Portland, I jumped in and grabbed rubber in all 4 gears heading out of the port! Man that sucker could flat out fly!
You can build a brand new one!
http://www.mustangandfords.com/parts/mump-0605-ford-small-crate-engine-guide/
You still have the K code Mustang?