I'll disassemble and clean, for sure.
I'll leave the bosses, stud and vent tube, thanks. I took the choke flap off long ago. I sealed the rod hole then.
This is why I want to remove the air horn. I don't know if it will improve air flow, but it can't hurt. I have 1" clearance between the lid and the front (higher part) of the air horn. I can't put a taller filter in it because I only have between 5/8" and 3/4" from the top of the air cleaner to the hood. It has a 3" tall element now.
It has an old gold Moroso on it. It doesn't look like the one TT5.9mag shows, though. I think it's from the 70's. It was on a friend's garage wall for years. It probably precedes the design of the nice one TT5.9mag shows?