American 40mm anti-aircraft guns (Bofors-US Navy)

The Floating Drydock is a great source for drawings and information. You might also find a copy of the August, 1988 copy of 'Fine Scale Modeler'. There is a great article by Bob Santos on scratchbuilding a quad 40mm mount in 1/32 scale. Should provide you with a few tips for your project. Good Luck. I also have a few pictures of a twin 40mm mount if you're interested.

Check out The Floating Drydock, they have plans & photos (sometimes too many).
Link: http://floatingdrydock.com/
Some of the metal 1/32 gun kits are good, some better--all seem to need a bit of work. Such is life. I've used the H-R 1/32 bofors kit, but it didn't look much like the kit when I was done (removed the train & elevation motors, replced the sight, fixed part of the right side plate, and replaced the barrel with some turned brass. All that to make an "improvised" 40mm half-track nount.