anyone here ever painted their Edelbrock intake?

To get decent paint adhesion you need to get it really clean, then use a good aluminum specific primer. I used a greenish yellow, military issue, zinc chromate back in the day, not even sure if you can buy it nowadays.
As for cleaning, I prefer a good dunking in carburetor cleaner, followed by a hot water rinse, then blown dry. This is about the only way to get a used one with crud in the the ports and heat riser passage clean, but you might get away with scrubbing it down with various brushes (bottle and otherwise) in a tub of simple green (full strength at first, then diluted with water), followed by soaking the entire piece in acetone, followed by an air dry.
Sanding the primer smooth after it has filled the pores of the cast aluminum and putting the paint on heavy enough to let it flow out should give you a smooth surface that's easy to clean.
I'm skipping the paint and powder coat options and having mine ceramic coated.