The Chevrolet Express 5.3 V8 310hp (2008 - 2014) produces 310bhp and 452Nm in standard form. Our Stage 1 ECU tuning file raises output to 330bhp and 480Nm, a gain of 20bhp and 28Nm, with no hardware modifications required. The file is delivered through the ByteFLASH portal and is ready to write to the vehicle.