Which Carb??
The 600 cfm units (Carter or Holley) for stock to minor mods.
650 (Edel AVS) or 670 (Holley) for typical mods and small cam. Increased gear and stall would bennifit even more so.
750 cfm carbs for some serious ground pounding rides. Increased compresion, large street cam and 3.90/4.10 and up gears. Best if you use this carb for a well built street machine or street/stripper.