Your looking at spray pattern. Do you have marine bowl pistons? There are a few venders here that can sell you some nice injectors with the right spray pattern that can be just as much as a new set of marines.
i havnt had a reason to take my head off so im not 100% sure.... but i bought it from a friend and he never said anything about putting in different pistons. all i know for sure is that they are 350horse marine injectors. with a weird size 5x.143 or something