Still working the air filter to cowl clearance issue. Kerry said that I could trim further on the intake manifold.
However, some users pointed out that the mixture cable lock screw interferes with the filter base seating fully on the carb. The cure for this is to remove material from the filter base where it meets the lock screw.
I marked and measured the location. Since the screw is about 1/4" in diameter, I used a 9/32" drill bit. After center-punching the location, I just drilled out material and test-fit it a few times. After deburring, the next step is to re-drill the filter base lock screw. This is an AN-3 bolt that goes thru one of four mounting holes on the filter base and into a hole in the carb body that must be marked, drilled, and tapped by the builder.
Since the base now sits "up" higher on the carb throat, I have to drill a new hole. Spent some time test-drilling holes in scrap and test-tapping them with a 10-32 tap.