Im hearing to go ahead and install the quarter windows after I finish most of the body work to avoid possible damage. So, what is the best way to do this?

Should the metal piece where the trackssit and the regulator be installed before the body work then when finished shimmy the window down into place?????

 

What year? Get a copy of the Mustang Body Assembly manual, NPN $16, for your year car. The installation and adjustments are covered quite well for at least 64 thru 68 (5 different books).
Jim

 

Almost positive you can install the regulator and all its components after. If there are mounts for the regulator to bolt to, they might need to be in place first.

 

Probably best to get the books, but yeah. Logic says you can intall the regulators now, and even the glass for that matter unless you are going to sand blast the interior of the car. But, there's no doubt you can do what Smothers says.