Ford 6.7L 1050 ft lbs TQ at 1,600 rpm, 475 HP at 2,800 rpm

If our C15 Cat makes 550 horsepower with about 40 psi of boost at 1400 rpm it would seem likely that a 6.7 spinning 2800 rpm would require similar boost to have similar airflow per hp if it were making 475 hp. Is there some reason to think that 38-40 psi should be unobtainable out of a stock 6.7 turbo?