you are guna want an lot of torque and a lot of power with a motor that can handle really high rpm's, ur also guna need a good transmisson, shift kit, tires, suspension, and breaks... and a damn good clutch. but the good thing about muscle cars (especially mustangs) is that its easy to get the wheels to spin, i test drove a stock 2001 cobra and i accidently down shifted to much on the free way (first time driving a sports clutch) and the tires started roasting, so if u do that and then turn the wheel and then floor it you'll get a good drift

but also make sure to get a good cooling system because you dont want to overheat. and as weird as it may sound the more grip your car has the better for drifting and once you get good if u want to b able to push your car harder tune it for understeer (as crazy as that sounds) if u want to learn more about this stuff i kind of obsses about muscle cars(especially mustang obviously lol) and racing so just message me or add me as a friend or something