There are some thread repair kit available nowadays...do a search for something along the line of "ford carb model xxxx inlet thread repair" to see if anything pops.
Alternatively, find an old carb somewhere and use the body piece of it you need.
that makes things a bit tougher, but still doable. if you are careful you can use a bottoming tap to cut new threads, and then use a brass fitting to replace the screw in filter, and go with an inline filter.
be very careful though if you go this route as you MUST BE ABSOLUTELY SURE that you run the tap in straight and you have no margin for error. if you dont get it precisely straight, you will battle fuel leaks.
more power to you. like i said use a bottoming tap, not a starting tap since you have no room to use a starting tap. the bottoming tap is flat on the end with no taper. and again make sure you get it as absolutely straight as possible. and take your time.
i have done things like that before, it happens regardless of how careful we are. i remember rebuilding a one barrel carb for my 66 falcon, only to find that i had stripped the screw holes in the body that held the carb top on. made my decision to convert to a two barrel carb and electronic ignition a simple one, and moved up the time table.