930/911 Turbo Headers with Heat Exchangers930 911Turbo Headers with Heat Exchangers 321 alloy stainless steel, 304ss heater boxes (available without heat exchangers, $400 less.) These short flow headers deliver more heat energy and exhaust velocity to the turbocharger, resulting in faster boost response, more torque, and more horsepower. Made to spec by Billy Boat Exhaust, they are a tried and true design used for over 25 years. TurboKraft has used these on engines making up to 600hp at the