Information provided by Eric H. (Uglyboost91)
Produced from 2002-2009 for the GMT 360 Platform, The Vortec 4200 is apart of the GM Atlas engine program, sharing design and components with it's 4 and 5 cylinder versions. The engine was a radical departure for GM and the entire auto industry at the time. Smaller and lighter than GM's own 4.3 V6 but producing 100 more HP, the 4200 was revolutionary. Despite it's great design, many Ward's best engine awards, and their proven reliability, the engine was sadly relegated to the single SUV platform and killed off in the heat of the Great Recession. Thankfully, today the engine is seeing a huge boom in popularity due to it's easy availability, cheap price, and robust build for boost and power adders.
4200 Development History
Development on the Atlas engine program started all the way back in 1995. At the time, GM was planning their next Blazer replacement, and wanted a new engine that would provide class leading power, refinement, and fuel economy. The engine also had to be scalable with different cylinder count varients (4 and 5) for eventual use in other GM programs. Despite a rumor that the engine was designed by Isuzu, its clear that the interviews with GM engineers and program managers has shown this is simply untrue. While GM would eventually share the engine for use in the Isuzu co-designed Colorado and Canyon, the Atlas engine program was 100% GM Homegrown design.