Transplanting a modern engine into an older car presents many challenges, one being the engine management system and gauge panel display. We chose to run a Mast Motorsports M90 ECM for a variety of reasons. Mast has been a leader in the GenIV engine family for some time, and they retail a whole line of ready-to-run high performance crate engines ranging up to 700 Horsepower, and when controlled by their M90 ECM, they are completely street drivable. We used the M90 ECM, a Mast harness, and their drive-by-wire throttle pedal in our GTO. The M90 features complete tunability, wideband O2 feedback, and knock sensor feedback to let high performance engines run on pump gas without issue. The L92 V8 engine uses electronic sensors on the block for vital functions, and the info is all sent to the Mast Motorsports M90 Engine Management system just as it would be in the 2007 GMC Yukon the in which engine was originally installed. The M90 features CAN network connectivity, which allows it to pass data from the ECM to other devices. Watch the video and read on how the we used very trick Mast CAN Network gauges to monitor the GTO's vitals in a clean, simple manner.