Which O-ring for M9593BB302 injector, Fast fuel rail leak
 

Injector #6 is leaking at the top where it goes into the Fast fuel rail. Using a mirror. I can see that it's fully seated inside the rail. This is the only injector that is leaking. I tried a new O-ring O'reillys part # 274571 on it and it still leaks. The bottoms where the injectors go into the fast 92 intake use the fast 92 O-rings. The one's for bottom fast intake are .62 OD, .31 ID, .15 Thick

The fuel rail brackets are the design that came out after 2012, the same ones that come in 146035-KIT designed to use the Fast rails with the fast 92 intake on an ls1.

Why is injector #6 leaking (2nd one from the rear on passenger side). Am I using the right O-rings on the top? Not sure what O-rings are being used on the tops of the others that are not leaking.

Bosch part number on these is 0280155759 which come stock on 98 volvo.
Factory O-ring replacement: volvo 30731375

Advance/OReilly: BWD - Fuel Injector Seal Kit, Part # : 274573
NAPA: CRB 212079
AC-delco 217-3366

Why are their 2 different part number 274573 and 274571? I thought all bosch injectors of this style were 14.5mm?