Here's another way too look at it, and how it was explained to me. GM used a "tier" system of how their vehicles were priced/sold, with Chevrolet at the bottom, Cadillac at the top. New technology or mechanical improvements would always be sold on a higher up the ladder brand first, for the most part. With Chevrolet being the bottom rung brand, it got upgrades and improvements last. That's on top of anything they could do to make them cheaper/easier to manufacture. As mentioned in an earlier post, GMC was considered an "upscale" truck, so it got engines from the higher up brands. Plus, when they did design their own engines, they got the improved mechanicals and technology, and a higher price to go with it.
