[DGthe3]

The least expensive (and most reliable) way for a manufacturer to get an engine to produce more power is by going to a bigger displacement. Bigger displacement results in a better power band because of the improved low end torque. A big slow turning engine is also more thermally efficient than a small high revving one. Fat power bands also allow for crazy overdrive ratios for improved highway economy.

The power numbers for the S200 are slightly misleading. When does anyway wind those up to 8000 rpm? For the most part, mild acceleration (up to 5k or so) in those cars gets you ~130 hp. The SS at the same revs produces about 400 hp. Hmm, triple the engine size, triple the power . . .

Now for Ford. They don't have a 5.0 that produces 400 hp. But they are expected to introduce it into 2011 MY vehicles. One way that they get the improved power is through direct injection, something that GM is working on for their next generation of V8's. DI allows for a ~15% increase in power while improving fuel economy slightly. So without it, that engine would be making 340 hp or so, which is less than what the LS3 makes on a hp/L basis.