Top-loader

Will it bolt up ? Yea. Will the shifter be in the correct position for your car ? Maybe. Check out David Kee's site www.4speedtoploaders.com to check if the tail housing has the shifter bolt pattern where your car needs it. If anything you can swap out the tailhousing for the correct one if need be. The length should be the same as your's needs.
 
D. Hearne is correct.

For a Mustang, you should have a 14" tailshaft that looks like this one I have on ebay:

tailshaft.jpg