rjwz28

But that's my point: GM's pushrod V8s have always been able to get better fuel mileage than their smaller-displacement dohc counterparts; so how would it be advantageous for them to start with a less efficient design when building a new powertrain for the Corvette when they could add all of their most recent advances to the current engine with slightly less displacement and easily meet the expectations of both the Corvette faithful and (not instead of) CAFE?

MPFD

iTrader: (5)

Over head cam valvetrain is more stable at ultra high RPM and a variable vein turbo is about as close to displacement of demand as it gets. I'm not saying that pushrods are a bad design I love LSx motors almost as I love my rifles (and thats huge). But most people make their association of over head cam and poor fuel economy based on Fords OHC motor history. When actually alot of it had to do with it bein a poor design over all. Ton's of cars are built today with OHC engines that make excellent fuel economy. My work car (Ford focus) averages 34 mpg. My previous work car (94 SHO) had a 3.2L 32 valve OHC that made almost 30. Could a pushrod motor do any better?

Cafe standard's: Corporate Average Fuel Economy (CAFE) is the sales weighted average fuel economy, expressed in miles per gallon (mpg), of a manufacturer’s fleet of passenger cars or light trucks with a gross vehicle weight rating (GVWR) of 8,500 lbs. or less, manufactured for sale in the United States, for any given model year.