Ok, I realize I am not the smartest person in the world but I have a stupid question about pushrods. GM has in its arsenal some amazing engines. Let's take the LS2, for example. It's compact, it's rugged, it gets good gas mileage, and it's relatively light. It makes massive amounts of horsepower. Why does GM not just use the LS2,LS6 across all of it's large vehicle range rather than mess around with Northstars and the new Northstar replacement, whatever they're called?