Do a Google search for Mustang GT. Here is a a small reference to the parts, but no specifics, will give you an idea at least. CJ Pony Parts - Ford Mustang Parts
I'm sorry, my response wasn't meant to be mean spirited. Since you are a founding member, with a documented true 66 Fastback GT car, I thought you were kidding around.
The GT option included stiffer springs, larger sway bar (as mentioned above), better shocks, quick ratio (for the time) steer box. It also included manual disc brakes, dual exhaust through the valance, GT stripes and badging... I *think* that's about it. A good search here, or through a couple of Mustang books (like Colin Dale's Original Mustang 1964 1/2 -1966, will get you a full answer.
Man, that original window sticker showing your car as a "true GT" makes the car even more valuable. If I could please suggest having the car looked over by an MCA concours judge before you start making changes. You may be better off to sell it, and buy a nice C code. You'd be way ahead money wise.
It's your car, but as a fellow enthusiast, I'd hate to see you do something irreversible that you'd kick yourself for down the road.
66 Runt, No offense taken. I was just trying to find out if it came w/ a rear sway bar.
My Dad gave me the car as a gift when I retired from the Navy. It has been a part of the family since 1984.
Well the car has had some damage as the original owners campaign raced it and it was hit in the left front , which was replaced. That piece replaced had the VIN number on it. So The only numbers I have are on the warranty plate and the window sticker. The Second owner cut holes in the doors to put speakers in it. However he didn't get to the radio, it is still stock. I still have the 4 speed and the A code 289 that came in it although was modified. It also has a really odd set of traction bars, they are like the traction masters however they allow you to adjust the spring pre-load. I have no idea when those were put on. Most of the changes are not permanent as I still have most of the parts.
That is a good idea to have the MCA check it out but I can tell you now it will not pass a concours inspection.
Sorry to hear about the damage. I got all excited for you when I heard you had the original window sticker. GT cars are not incredibly difficult to fake, so having that sticker can really make a difference on resale.
But most importantly it's your car to modify as you please. You might send a PM to Opentracker, he has a lot of quality suspension stuff, as well as track experience with these cars.
From what I see (and my personal experience) the cars can be made to handle better without a rear sway bar. John (Opentracker) can give you some great advice. I'm running his roller perches and upper control arms, and am *very* happy with them.
The traction bars are different. They bolt forward of the spring and the rear bolts on the shock/spring pad on the rear with what looks similar to the forward end of a strut rod w/ two muffins.