Street Demon or Edelbrock AVS2 or ?

Just to be clear, the AVS has the spring loaded air door. The “afb” version has the counter weights. Both of the Eddy’s use the AFB base with the slots for counter weight shaft. I run a 800 AVS, and it is WAY out of its comfort zone, but still working. It really needs a secondary transition system like the carter AFB. The small port that the counter weighted butterflies pass by. Add that the AVS spring is pretty fragile…..and you get lean spot on secondary opening. Also the secondary emulsion tube necks down at the bottom. Again, mine is way out of its comfort zone.
What cubes are you running the 800 on? If the secondary emulsion tube is pinched at the very end then that is the limiting factor in fuel flow on the secondary's not the jet size if it is bigger. Can you post a pic of the secondary booster emulsion tube?

You can also make your own springs if you really need a stronger one.

Making Springs At Home