They are approximately an inch shorter on both measurements than the 64-73 mustang shocks....the mustang should measure some where around 16.5" and 10.25". The mustang shocks will work.
The front shocks are still available from places like autoxone.
[addsig]
I bought a set of adjustable Competition Engineering front shocks and had the lower mounting bracket pressed out of the old shock and installed into the new one (So, don't throw away the old set!!!) I will write back with the model #.