We love Ford’s new 5.0 engine for so many reasons. It is the perfect marriage between a traditional name, and modern day technology. The naturally aspirated 5.0 engine brings back vivid memories of the days when the 5.0 engine ruled the streets. Australia is getting their own version of the 5.0, codenamed “Miami”, and new details are emerging on this engine.

The Mustang News reports that the Australian Boss 315 and 335 engines, which will be found under the hoods of the Falcon GS and GT, don’t make as much horsepower as you might expect from a supercharged 5.0.

The Boss 5.0 315 (which stands for kW, Australia’s horsepower measurement) makes about 422 horsepower, while the Boss 335 makes about 449 horsepower. How could that be, when the base 5.0 makes 412 horsepower, and the naturally aspirated American Boss 5.0 engine makes 440 horsepower? It all comes down to two things; emissions standards and durability.

Australia had adopted the Euro IV emissions standards, and will soon adopt the even-stricter Euro-IV standards. Ever wonder why most European sports cars don’t come with big V8 engines? Emissions standards. Australia also has a much harsher climate than America. Much of the interior of the Land Down Under is nothing but desert. Ford had to bump the compression ratio down from America’s 11:1 to just 9.25:1. The supercharged 5.0 also uses less than the 5 lbs. of boost – around the boost pressure many factory superchargers use.

While this may be disappointing for Ford fans, there are some additional benefits. This engine replaces the supercharged 5.4 liter engine used in previous Falcons (as well as our Cobra R Mustang), and its aluminum block makes it 103 pounds lighter than previous engines. Still, we were hoping to see something more along the lines of say, 550 horsepower as opposed to 450 horsepower. Let us hope those emissions standards don’t make it over to the U.S. anytime soon.