I kinda disagree, there's a good reason almost nobody makes a modern engine with wedge chambers and 2-valve heads except for GM and we all know how resistant that company is to trying new ideas. There's so much more potential for overall efficiency in the design of the new Hemis. Like rumblefish said the way to go for OEMs is to use short-duration roller cams with good lift and heavily R&D'd computer-designed ports that flow massive amounts of air even at low valve lifts. That's why a new Hemi will gain 100+ HP with just a cam swap. Combustion efficiency has also improved that's why you now see factory 10.5:1 engines that are made to run on regular or mid-grade gas.Remember the LA was designed as a quick & dirty lightweight replacement for the poly engines back in 1964. 50 years is an eternity when you're talking about technological advances. BTW of all the new tech features mentioned in this thread 4-valve heads are BY FAR the most significant efficiency improvement over the years. VVT, variable intakes etc. are secondary they actually don't do a whole lot on their own.