Gomer, if you didn't get them from Blackline racing or someone like me, you should take them apart. New carbs NEED to be taken apart and CLEANED to hospital specs. There is often a lot of machining junk left in them. All orifices, reservoirs, and passages need to be blasted with carb cleaner and air dried. I usually use a blow gun with a rubber tip, set to about 20-25 pounds.
After cleaning, set the float height and drop(I use 11mm and 25mm), and give yourself a half-turn of the idle speed stops off of fully closed throttle plates. Also, open all 4 idle volume(mixture) screws 1.5 turns from closed.
Then once they're clean and set up, you can install them and run 'em.
Don't forget to set the fuel pressure at no more than 3 psi for Webers.
Cheers.