Here looks like a good source for those old carb parts. Spart, you still looking for little jets, here you go.
http://www.ebay.com/itm/Autolite-Motorcraft-Ford-2100-4100-Carburetor-New-Jets-260-289-302-351-390-427-/200686071001?pt=Vintage_Car_Truck_Parts_Accessories&hash=item2eb9d26cd9&vxp=mtr
http://www.ebay.com/itm/Autolite-Motorcraft-Ford-2100-4100-Carburetor-New-Jets-260-289-302-351-390-427-/200686071001?pt=Vintage_Car_Truck_Parts_Accessories&hash=item2eb9d26cd9&vxp=mtr