I don't understand 379MV6GMC-K3000, the 406 and the 350 are both small block chevy's. Why dog one and support the other?

Not everybody is crazy about a diesel in there truck. I had a 2000 model 3500 dodge and I LOVED my cummins, but it was a work truck. I drive a gas burner in a half ton , run to the store, truck.
But thats me.