The last hoorah for the 60 degree V6, which debuted WAY back in 1980 in the X-body, and was hardly a cutting edge engine even then, got VVT in both the 3.5L and 3.9L variations. And, truth be told, they pretty much fixed most all that was left of that engine family's shortcomings by then. Fixed the chronic intake gasket leaks the 3.1L and 3.4L had with torque limiters in them, fixed the head gasket blowing issues the 3.4L had with a proper MLS head gasket, further tweaked and improved the engine management system, and in some models mated to a more modern 6sp automatic provided by Aisin. Those 3.5L and 3.9L engines were pretty good, and reasonably powerful even if they didn't have a lofty peak HP number on paper. Then, once they pretty much perfected this engine family, which took 30 years, they dumped it and replaced it with the miserable chain chucking turd of the 3.6L.
So, the old pushrod engine quietly died in the 2011 Impala in the back of rental lots and motor pool fleets. Unloved, unknown, and forgotten.
They also use, and still use, VVT in the V8s and truck pushrod 4.3L V6. Along with cylinder deactivation, which causes a lot of problems because these have no tolerance for lack of PM. Which happens quite frequently in company trucks. And why we spend so much time replacing engines in them.
Something the older GM trucks didn't have to worry about. The old 4.3L (which was, to all you rednecks, essentially a "three-fifty" with two cylinders lopped off), was a pretty tough engine. It could run with half its crankcase empty and still get the job done.