Ford 9" in 1965 Barracuda...an option?

Thank you all for your your feedback and input! I really appreciate it! I really do not know much about differential changes or what to do regarding this option. I would like to keep my same bolt pattern/Cragar wheels due to the expense to try to buy other wheels. I have thought about trying to go disc brakes on front and rear vs. stock drums also. I've got limited funds and 72 years old with minimal differential experience or changing from a stock set up to a different type set up. Any input and advice is greatly appreciated.
The reason I've even considered this is I can't find a used 7 1/4 differential with sure grip and the 9" Ford has an extra unit with Posi Trac. I would like to have the positrac setup one way or the other even if I had to trade the Ford 9" for and 8 1/4 or other set up that would work in the application, retaining the current bolt pattern and wheels.
I guess I'm asking for more than I can expect...don't know?!
Thanks