in 1964 Chrysler made the 426 RACE engine for NASCAR. it beat up so bad on every one that NASCAR made a NEW rule that the auto maker had to make a min of 500 engines to be stock. so for 1965 Chrysler boycotted NASCAR. and Richard Petty went drag racing. thats when Chrysler made the STREET HEMI, really a different engine, much milder, way different carbs. cause in NASCAR they had to use only one carb.