I've done some funky things with aircleaners. If you want to use the original (from the aftermarket aircleaner) filter media and cover, it's easier to make a mounting plate to match your S&S, and weld it to the aftermarket aircleaner backing plate. Grind it smooth, paint it black and it looks like it belongs there....
Another method is to cut the back out of the a backing plate that fits, and weld it into the one you want.
use a piece of 1/2" aluminum cut it in a circle to match the throat of the carb drill the carb bolt pattern in it so the screws fit.
Now put it on your carb and put the aircleaner backing plate up to it mark your bolt holes and drill to match so you will have two sets of mounting holes one for the carb and one for the aircleaner.
cut and shape the aluminum to the shape you want then polish it.
thats what I did to mine.
tools used ,jig saw with metal blade,hand drill, polish wheel.not much else besides some hand tools,screwdrivers wrenchs ect..
hope this helps All it is is a adapter spacer.