You CAN make a six run.... A freind of my dads is running a 301 Jimmy I-6 in a 57' Chevy 2 dr sedan. The car is all steel and running a 4 speed. He runs the car in the Nostalgia Drags sometimes(he has owned/raced it since the early 60's with this setup). He was an IHRA Natl' Record holder for years with that car running at Englishtown Raceway Park.
I have personally seen that car pull the front wheels 2 feet plus in the air and carry them for the first 40-60 feet. Sounds neat too!!!