Double Pump vs. Standard.... Good? Why?

Just my 2cents. I run a 650 AVS, 3,500stall and 3.91s and theres no lack of getting out of the hole with my 318. Turned 1.9 60ft at 5,200ft which isnt too shabby...

Double Pumper vs 'Normal' as in 'Vacuum Secondary has the advantage, usually, for Manual cars or cars with high stall converters and low gears. Due to the fact it instantly runs secondaires and feeds the motor all four barrels based on how much throttle, and not just two barrels...then four barrels based on vacuum like a vac. secondary. This is good for manual cars and high stall autos because when dialed in right, you can usually get a better launch due to it being able to rev up (stall) or you rev it up (manual) before the load of the car hits the motor. A vac secondary will run 2barrels till the motor has a certain (tuned) velocity going through the carb to open whatever secondary type it is (holley the spring setup, eddie with the performer/afb or the avs). Just the motor idling will probably sound a little snappier with the double pumper....until to stick the load of the car on the engine and it just wont be able to handle that much fuel/air and will bog it out.

So unless you are running a manual or a wicked converter. In my opinion, the double pumper will hurt. Your AFB/Performer carb will be able to work best, actually a avs would be best, but the performer will work. Its just a much bigger pain in the *** to tune when the secondarys kick in (disassembly of the carb and grinding or adding weight to the carbs counter-weights), where as a AVS you need a screwdriver and Torx head to adjust the secondarys (WELL worth the money over the AFB/Performer)

Just my 2cents. I think the double pumper will hurt, probably a chevy guy told you that lol.