64 Barracuda rear end

The "Chrysler Performance Upgrades" book by Frank Adkins has a table with details of axle lengths and hanger spacing, etc. I recommend it. I struggled with this on my 1965 Valiant -- I wanted big bolt pattern and gearing options. It looked like I would have to go to 8 3/4 to get everything I wanted. And that would be expensive. In the end I went with a Ford 8" from a '65 mustang (v8). It's built just like the bullet-proof ford 9" (except not ash heavy-duty as the Ford 9"). Axle lengths and hanger locations matched the '65 7&1/4.