Never heard of a BG500 pump, but have experience with the BG400 many years ago. The 400 was fine at the track, but on the street (for longer drives) it would get super hot, and the pump shaft seal would leak, then burn-up. If you’re planning to run one on the street consider using the BG step-down box (if you can find one). I repaired the pump, sold it. From then on I’ve only run MagnaFlow/MagnaFuel 500 pumps or Product Engineering 4450 pumps on street/track.