Wow, wow. I remember driving a new 69 Challenger from Mobile to Miami Beach, slap shift (?). The owner and I took the straight-on-through trip via the interstate and he kept urging me to "step on it" when we passed other cars... It didn't take long to pass I'll tell ya!
FYI, and not to be nit-picky at all, your adventure may have taken place in '69, but the first Challenger came out as a '70 model, and the fancy shifter on the Torqueflite auto was known as the Slap Stick.