We barely let the engine cool after the drive down from Monterey before rolling into MD Automotive in Westminster, California and strapping the 2012 Ford Mustang Boss 302 to its Dynojet chassis dyno.
Ford claims the Boss produces 444 hp at 7,500 rpm and 380 lb-ft of torque at 4,500 rpm -- a substantial horsepower gain over the stock 5.0 GT's 412 hp at 6,500 rpm and 390 lb-ft at 4,250 rpm. Ford reengineered just about every piece of the Boss 302's engine so the gain should be substantial. And it is.
Hit the jump for the details.
A careful look at the Boss' power trace shows it making power all the way past redline. In fact, the fuel cut appears to be about 7,700 rpm -- an astonishing speed for a V8 this size. With coolant and oil temps stabilized, we saw three runs within five peak horsepower of one another. And when you're talking about 415 hp, that's pretty much dead consistent. The lines laid down right on top of each other.
But how big is the improvement relative to a 2011 Ford Mustang GT 5.0?
Ford claims a 32-hp difference between the peak output of these engines and we measured 36 hp. Perhaps more relevant is torque, which Ford claims to be 10 lb-ft lower in the Boss. Not according to our numbers. Sure, the torque peak comes 900 rpm later, but there are two more lb-ft to be had from the higher-revving engine. Of course, at 4,350 rpm, where the GT makes peak torque, the Boss trails by about 11 lb-ft.
What the data doesn't tell you is how transformational a 900-rpm increase in peak power is between these two engines. At the GT's power peak of 6,650 rpm, the Boss is alreay making 24 additional hp. And it continues over the next 900 rpm to pour on the coals and churn out another 12 hp.