I always call it a ST400 because I'm a Buick nut.
Like the factory chrome wheels of that time, they aren't "Rally wheel" (I'll punch you in the throat
) They are "Sport Wheels" or "Road wheels".
The 64 ST400 also didn't have the switch pitch converter that the 65 and later had which has a variable stall speed controled by a simple 12 volts to it raising the stall by about 500 RPM. It was controled by a micro switch on the throttle linkage at the carb. The idea being when you have your foot off the gas at a light the stall went up so the car wouldn't be "pulling".
Brian