The link below is to BLP, which is Bo Laws Carbs. I just used one of their kits to repair a stripped squirter screw on a Ford tri-power carb. Not easy - best done on a drill press or a verticle mill to get hole reamed centered and straight. Hole is reamed out and an insert is pressed/locktited in that has threads and the fuel slots. Site has a lot of neat stuff.

http://www.blp.com/frmCatalog.htm