Fuel Injector Replacement

Does anybody know how to remove the fuel injectors in a TBI? My mechanic mistakenly put 305 injectors in my 350. It's taking forever to get a set out of a junk yard and the old injectors work great (they had to be replacing because the unit cracked where the fuel lines thread in). I have my old ones apart but can't seem to remove the actual injectors from the housing they sit in. I took the plate off, and it looks as though they are pressed in, or something is holding them in. I didn't want to pry on them and risk breaking anything. Any help would be greatly appreciated. Thanks.