Secret 1973 SSR Pygmalion muscle car
To get the 1973 SSR Pygmalion muscle car (one of the best and fastest muscle cars in the game), you must find and complete a specific Prepper Stash. Go to the far southeast corner of Henbane River in Faith's region to find McCallough's Garage off the main road. If you start at Hope County Jail and drive east on the paved road, you will find McCallough's Garage. At the old garage, break through the boarded-up doorway behind the garage to enter it.
Inside, press the indicated button at the end of the path to open the garage door. Backtrack to the front and go under the open garage door, looking left for a door that leads into a room full of crates. Proceed through the crates until you reach the restroom, and grab the key in this area. Then, go back out and to the interior room through the front door to reach a large set of metal doors. Use the key you just collected to unlock the vault. You will find the 1973 SSR Pygmalion muscle car inside and complete the "Getaway" Prepper Stash. Once the car is unlocked, you will be able to visit any car store and select it from the menu to spawn.