From a $12K IROC-Z to a $30K Buick GS 455, these 5 sleeper muscle cars are still affordable — but not for long.

Rear view of classic 60s muscle cars at vintage automotive exhibition. - Mr.Nikon/Shutterstock Not many other segments of vehicles have left as indelible a mark on the American psyche as muscle cars.

The first of the factory-supercharged American muscle cars was the Studebaker Avanti R2 in 1963. It arrived during the muscle ...