Well, when I first got my detuned (660hp) 358ci motor, I was tuneing with the speed pro lap top in data log mode. I was spinning so fast on slick pavement in second gear that I revved it past its optimal shift point of 7700 or so. I let off and went into third. In reviewing the data log, I hit 9100 rpm. My motor is done at 8000 rpm or so and I have since set the rev limiter at 8200 rpm to be safe. I hit it every once in a while. I also have the stainless steel valves and not titanium like the cup guys run so over 8000 and it could be trouble so it is cammed accordingly. I am probably on borrowed time with this motor as it has been punished regularly. I keep
oil in it and my fingers crossed. Scott