Even facing some resistence from the (stereo)typical GM's most loyal customers, the downsizing is a reality that can't be denied. However, even famous for its bigger engines, as a global car manufacturing group, General Motors is ready to face competition in the newer trend in engine development.
A clear example is the 4.3L Vortec V-6 engine still offered in basic versions of the Silverado. Some versions of the 2.0L straight-4 Ecotec fitted with turbo and intercooler can deliver the same 260lb.ft. torque rating in a lower engine speed, as well as more than its current 195hp rating. Then, not just due to the smaller weight and displacement of the engine, also since a lower speed is required to do the same jobs it turns the 4cyl turbocharged more efficient.
Drawing above is only for artistic purposes, Chevrolet Astro was never used by any police department in Brazil
In other markets, most notably european countries, GM has been successful with the downsizing. Some of its models are currently offered only with turbocharged engines in Portugal, such as the Opel Insignia, currently offered in the american market as Buick Regal, featuring a 2.4L Ecotec non-turbo (182hp/172lb.ft.) not avaliable in its european counterpart and the turbocharged 2.0L in a 220hp/258lb.ft. version (this setup would already be enought to replace the 193hp/250lb.ft. 4.3L V6 in the Blazer). Surprisingly, in a segment where 4-cyl engines are perceived as "less luxury", GM is not offering the 2.8L turbocharged V6, that with its 325hp/320lb.ft. could beat the 3.6L currently used from the Chevy Camaro to the Cadillac SRX (without any V8 option in the current generation) delivering 300hp/273lb.ft., again, at higher engine speeds. Even the Vortec 4800 V8 with its 295hp/305lb.ft. could be replaced by the 2.8L without any prejudice in the performance. All of that with systems already avaliable in GM's portfolio.
So, seems like GM is ready to play the downsizing game. What about you?