tough question-back in the day i raced my 71 340-4 speed Challenger against a 67 4 speed 440 GTX-it was prtty much a toss up-winner depended on who drove the best race-at that time my 340 was running 3.23 gears and the GTX was running 4.10 gears-i wonder what would have happened if i had 3.91's in the 340 challenger---previously the GTX had 4.56's---with the 4.56 gears it wasnt even a close race-the 340 car won every time-the GTX just didnt have enough top end to beat the 340