I used to run a '70 Challenger that would run mid to low 12's. It was an original 340 car (340 was long gone by the time I got the car) and had a 440. The rear suspension was the original tired factory springs and an open carrier 8 3/4 w/3.23 gears. I put a locker in the carrier, and used 1" wide U bar steel to make clamps for the springs.
