63 lb injector at 42-43 psi would be virtually tapped out at 80% DC. If your BSFC is higher you would need something closer to a 75 lb injector or higher.

I I would guess with those parts that combo would be more closer to a 6k engine than 5k.....IMHO.

It will spin to 6k+ I would guess as the supercharger will make up to 8psi at that speed. If you ran out of injector at 5000, you'll need a lot more. I'd go at least 30% bigger, maybe even 50%. If you can get up to 6500 safely you'll be making some serious power, like 900+. I'd geuss you were making 650ish at 5k.

Like others have stated you will what to spin it alittle higher. If it does make 6lbs at 5k it will be a few lbs higher at 6k. That blower will support 950-1k hp on pump gas in a marine application with that good intercooler. The j trim is only slightly smaller than a procharger m3.

Some interesting opinions! I'm sure the motor can spin up to 6k, but anything ive heard is "under five, Stay alive". I want these to last.
Sooo, I have 72lbs injectors and this was based on recommendations of the tuning software using 775hp as the brake hp. BUT I've had a lean issue lately (just redid the heads after I burnt some valves). Trying to find out if it's the injectors or the tune.
It seems most ppl think that I have enough injector.

Is the fuel pressure staying consistant?

Do you have gun drilled fittings on the fuel system? They cause cavitation and that will give a lean condition. Any sharp corners in a fuel system is bad especially in the suction side to the pump.

i have no comment on injector sizing but when everything is right i would say 875 hp at 6000 rpm,+ or -.30.forget about a 5000 max rpm.you have the correct parts to run to 6000 all day long.

Yeah you weren't making that much HP at that RPM. You've got another issue.

Maybe on sailboat sites, but not here will you here this.