You will here some say use the smaller carb if your not turning over such & such RPMs, there is alot more involved then just "that", you have to take into consideration of the intake/cam/heads/gears/stall/exhaust, most think a larger "primary" will give less power/torque & throttle responce, this is not always the case, if your running a fairly stock 360 with a stock stall & gears then yes, the smaller primaries will do much better, when you take into account the added gearing & better stall, intake design (more plenum area), the increased RPMs at a lower MPH (not just total RPMs), the larger primary carb works better all around, you'll get better throttle responce/excelleration/mid & top end power.
Duletch ( i think thats how you say it) tested this theory out on a 383, by the time he was done, he increased HP & torque big time going from a 500 or 600 CFM too an 850 Mighty Demon that flowed over 900 CFM, & this 383 was on the mild side, just your basic street engine, if i'm not mistaken, he increased the HP by 50+ & torque around 30 just from carb changes, the only thing was the torque dropped a tad in the RPM range with the Mighty Demon, but it increased enough to make it a better
choice from the previous carb.
