Ihad my bigmouth flow tested and they were just about on the mark , tje flow more than i need with room for improvement should i get a bigger cam and want to set the rev limit a bit higher . with the right cam and intake I'm sure i could get close to 600 hp , i'm at 510-520 now my setup now drops off at 5300 rpm , i want it to peak at 6200-6500 rpm