It's why Ford is so proud of the Boss 302, winner of the 1970 Trans-Am season with legendary driver Parnelli Jones behind the wheel, and why the street car has become a legend. But ask Jim Farley, Ford's head honcho of marketing, about the 2012 Mustang Boss 302, and he'll tell you that it's not just about building a remake of the original. "This is not a nostalgia project," he told us. "This is not in any way trying to bring back the Boss. This project is so much more than that. If we wanted to do that we could take a 5.0-liter, put some stripes and spoilers and other upgrades on it and that would be it. It was not a means to an end. The Boss 302 was originally a means to an end. It was a production car to go racing. This is a completely different project. We were not going to do this project unless we could beat an M3 at this track." This track being the famed Mazda Raceway Laguna Seca.
Ford's engineers probably could have done some minor tweaking to the 5.0-liter V8 to reach their target goal of 440 horsepower (they ended up with 444), but they went all out to ensure that the engine was worthy of the Boss 302 moniker. If you go by the numbers, a 32-horsepower gain doesn't seem like all that much compared with the standard Mustang GT, but there's a lot more to this engine than peak horsepower.
According to Mike Harrisson, the Boss' engine program manager, the focus was to "make it breathe, make it rev and make it durable." The first was achieved with an all new intake manifold inspired by Daytona prototypes that features shorter runners for improved air flow at higher RPMs. Also improving the engine's breathing is a new set of high-strength cylinder heads that have been CNC ported on both the intake and exhaust side, a process that takes two and a half hours per head. Finally, the lift and diameter has been increased for the exhaust valves. And to make it rev? Ford engineer's swapped out the Mustang's entire valvetrain and bottom end to handle their target goal of a 7,500 rpm redline. The list of fortified parts – forged aluminum pistons, sinter-forged connecting rods, race-spec crankshaft and rod bearings, heavy duty valve springs and more aggressive camshafts – leaves little else to be upgraded and shows just how different this engine is from the standard Mustang GT's. The result is that the motor is stable up to 8,400 rpm. That leads us into durability, where Ford took the approach of testing out the engine in the motorsports arena. The first 10 engines assembled went straight to Multimatic Motorsports, who used them in their Boss 302R race cars. The team ran with the engines all of last season without a single hardware failure.
Ford says that the standard Boss 302 will lap Laguna Seca a second faster than the BMW M3 (the Laguna Seca package is one second faster still), and we're inclined to believe them. Ford actually brought an M3 for us to compare the two, but the Bimmer had some problems earlier in the day and we never got the chance.
The only weakness of the Boss 302 we encountered was with the brakes, mainly at the rear. The front Brembos were fine, but the 11.8-inch discs with single-piston calipers out back weren't up to the task of consistent hot-lapping. A few times the cars came in with smoke coming from the rear, and we couldn't do more than three or four really hard laps before they needed a cool down. Track addicts take note: new pads and maybe an aftermarket set of rear brakes should be on your shopping list.