I'm in the process of rebuilding a 600 cfm edelbrock (mech. secondaries and manual choke) and noticed there are a second set of butter flys in the secondaire barrels, they are only connected to a set of waits.. what are the purpose of these and would there be any benefits or harm to take these out?

Its going on a stock 305, only mod that will be made while the carb is on is headers.

 

The upper set of butterflies is an air valve, just like the Q-Jet; except that the ones in that old 50s model Carter from the Stone Age are controlled by weights instead of springs. Very crude. Effective on a car that's sitting still, or maybe on a 54 Pontiac straight 8 car that weighs 5000 pounds and has about 180 HP; but pretty poor for performance use by "modern" standards. But since you bought it, you're pretty much stuck with it.

It's necessary. You can't eliminate it. Just make sure it works as good as it can, that's the best that carb will ever do.

 

well i got it for free, so the only thing it really cost me was $40 for the rebuild kit... and its only a temp. solution while i work on my TPI setup