I recenlty purchaced some 720cc delphi top feed injectors from a friend with a mk4. I was told they would work but they need to be machined. I was curious as to what exactly needs to get machined. I found threads where people say the Rail side of the injector needs to get machined. However it looks like the Head side has a lip when you peel of the oring that looks like it needs to be taken down to fit in the grommet. The actual body though is measuring .312 and is to small to fit in the grommet. I have some RC 550cc injectors that messure .357 I know some people are using these and I was wondering what they have done. Thanks for any help that can be offered.