Your going to have to look around and see what's out there, that is correct for your application. I do not follow all of the various ones that have shown up on the market but we have tested lots of the ones that are supposed to be correct and they are not even close for the M8 application. Fine for a TC but no where even close to what it should be for a M8. If I started naming all the internet resellers here I would get a huge up-roar of complaints so I will just leave it at that. I stick to the HD ones for the most part and if I need more I get custom ones built for it, but those cost over 2 - 3 times what the others are selling for. Many are nothing more than stock car injectors being resold! The SE 5.5 will handle about 145 HP @ 6000 RPM. If your going to be running the engine above that then you are going to need a custom built set for whatever your doing, as none of the ones I've tested on the flow bench here have been correct and I can say I've got about 15 sets from various internet based sellers here. The closest ones I've tested were from GMR and while they are not exactly what I want, they have been the closest ones for a reasonable cost. The customs take 3 -4 months to get, and a single set runs in the 600 - 800 range which most are not willing to spend.