Anybody experiment with some kind of epoxy paint or powdercoat for inside quadrajet main body ? Plating is out of the question for now.

for what purpose?????

Surely you mean the outside face of the of the main body - similar to the carter AFB black main body?

If the inside bowl surfaces are so badly corroded you're looking for a filler - it's time to break down and spend a couple of bucks on a new piece.

The fuel evaporates out of the bowl and moisture helps oxidize the zinc and all kinds of electrolysis goes on too especially if customer gets water in fuel or somehow rainwater or condensation ends up in bowl and ends up with the white junk in the bowl.
Many carbs I have paid alot for a rebuild don't have protective coating inside and go bad right away. Strict Epa Regs have really made electroplating quite expensive, although we will be healthier, and our earth will be better with out the pollution. I have looked into electroplating.
I'd have to go into the buisness all the way and still would probably lose my shirt , pants , socks and underwear.

Losing the clothes may not be bad, depending who you're with..
The moisture is there every morning here in Ontario, as we have a big tempertaure variances each day. We use gas line antifreeze to drive out the moisture and keep the bowls clear. It's cheap, and the engines start while we're wiping the dew off the screen...

Do you have a picture of what you want coated? I might be able to use the same coating I use to refinish tubs. It's some might tuff stuff.

it's not rainwater getting in there it is this crap fuel that has ethanol. the ethanol is know for corroding the aluminum. i see this a lot with outboard carbs especially yamaha's. just ask any carb rebuilder and he will tell you the same. i'm on long island too try calling allstate carb in central islip.