Hmm. I don't know if I can see what's the problem here....
Do you have O- ring bungs in your inlet and the fuel rails?
If so, a set of injectors with ruffly the same length & diameter, appropriate connector and desired flow rate would do the job.
The O- rings can be switched out to correct diameter, if that's the problem.
I'd suspect something like this would fit (Ford 5.0- type injector):
Summit Racing SUM-240030-1 - Summit Racing Street & Strip® High-Flow Fuel Injectors - Overview - SummitRacing.com?
As for flow rate- 30- 40 for 500 Hp NA?
RS