Are your cast manifolds enough to keep up with your turbo motor? And at what point should you be running proper headers? Those are the questions we're asking this time on Engine Masters, presented by AMSOIL. Using a typical mill you'd find in a turbo street car, we're running our 630-hp 5.3 LS with factory exhaust manifolds and again with turbo headers to show you the differences in boost, backpressure, and horsepower.