built 400 problems

ive got a highly built 400 sixty over domed pistons decked block brand new comp cam with solid lifters but it raps out at 4000 rpm with no rev limiter rockers have been set and reset many times timed it many times sevaral new carbs differnt cams but can never get it past 4000 rpm....any ideas? need help badly!

Need more info. What heads? Headers? Carb? Intake? Distributor? Fuel octane? Grind number?

Was the cam "degreed" when it was installed?

Fill in the "blanks" and I may be able to help.

Jim