First, how modified is your engine? From past experience, a 500 holley just would not be my choice for a street engine. The out of the box calibration is way too rich for a 2000cc. The 350 or even the 390 4 barrel provide much better response. The local dirt guys run 500s, but they either idle or run 8000 rpm. I'm sure you'll receive several more opinions here, but I'd like more engine/application info. JT