All Gen IV truck engines are equipped with displacement on demand (also known as Active Fuel Management) and many have variable valve timing. Neither is conducive to longevity or simplified wiring. The engine already had a ticking lifter, so I opted to eliminate the DOD system with a bunch of goodies from Tilden Motorsports. Not trusting myself to perform the internal engine surgery, I took the engine to LS guru Kevin Stearns to exorcise the DOD demons and add some go-fast goodies. You can read more about the details of this on the Four Wheeler Network: <a href="http://www.fourwheeler.com/how-to/engine/1809-deleting-afm-and-upping-power-on-a-gen-iv-5-3l-ls-engine/" title="" target="_blank">bit.ly/2AJhV7h</a>.