Working in GM dealerships since 81(?) Know/known/dealt with many over the years. And deal with one most every day now working at his fathers AC Delco warehouse. Like any other career, some good, many not. Do to thought process(?), common sense seems to be absent. And don't waste time arguing, their never wrong . Ya, right! Done with rant about them people...
According to GM, the heat x-over is for faster cold weather heat up, and choke coil operation. Like mentioned above, the location is wrong for exhaust pulses. But will say this. Heat = energy. So the higher the engine operates at(up to a point), the more power it will produce.
