As the 1960s drift further and further into the past, examples of classic muscle cars you can just jump in and drive are getting harder and harder to find. If you need a rare Ford that fits the bill, the Shelby Mustang that just popped up on Bring a Trailer has your name all over it. While it's far from a preserved classic that belongs in a museum, it's got all the right mods in all the right places that make it one heck of a driver. The Rundown on This 1969 Shelby Mustang Mustang Gallery 4The car in question is a 1969 Shelby Mustang GT350 fastback. Yeah, that's a lot to unpack. For starters, it's a fastback, which is enough to have muscle car enthusiasts tripping over themselves to get a look at. Two, the Shelby name on it makes it a special part of high-performance history that everyone would love to have in their garage. And to really pump up that cool factor, it's said to be one of just 637 cars produced for the model year.As I mentioned earlier, this car is far from stock. Some modifications have been made to up its potency. The 351 cubic-inch Windsor V8 has been rebuilt and outfitted with an Isky camshaft. Out back, the differential has been set up with a 3.89 gear. Those two mods, paired with the fiberglass front end, make for a hard runner. Thankfully, that rear gear also won't have the car too tightly wound on the highway when you're cruising. That's good to know, considering it's still running a close-ratio Toploader 4-speed. 1969 Shelby Mustang GT350 Fastback Highlights One of 637 cars made. Rebuilt and modified 351 Windsor V8 with Isky cam, headers, Holley carburetor, aluminum flywheel, and modified exhaust. Rear tail panel has been modified, parts to reverse changes are included. Other mods include repainted exterior, Vintage Air climate control system, updated stereo. Unknown mileage. The exhaust has also been modified. It's been rerouted, and the glass pack mufflers are sure to give it a mighty roar. Back at the engine, a set of long tube headers work with that cam to help theWindsor breathe. A Holley 4118-S carburetor is also at work feeding the driver those sweet, sweet horses.Some exterior mods have also been made to this car, but nothing distasteful. The tail panel has been slightly tweaked. The plate was relocated, a GT40 gas cap was installed, and different tail lights were added. The seller is tossing in some parts to reverse those changes. A GT350 You Can Drive The Wheels Off Bring a TrailerRight now, there are sure to be some purists blowing a gasket reading about how a prime Shelby Mustanghas been modified. So, what? What's awesome about this car is that it looks like the part and has badges to prove it, but it's not one you should hide away. It's built to be used, with plenty of mods made in the name of that. Some more upgrades we didn't talk about but really make major improvements in this department are the Vintage Air climate control system and updated stereo. The fact that it also doesn't have the factory paint and unknown mileage makes it even better. That means you don't have to worry about messing it up. All you have to do is get in and drive the wheels off of it.