Ford Boss 302 Engine

Ford Boss 302 Engine

Two generations of Boss 302 Mustang sports cars—the 1969-1970 original and the 2012-2013 reintroduction—have been produced and, while their model-specific engines (the 1969-70 Cleveland-Boss variant and 2012-13 Coyote-Boss variant respectively) share their 302 cubic inch (5 liter) displacement and "race engine for the street" personalities, they also show how advances in engineering and manufacturing techniques have made possible modern "muscle cars" that greatly outperform the American-made muscle cars produced in the era 1965-1970. This is exemplified by the 2012-13 Boss 302 Mustangs, which, powered by the Coyote-Boss engines Ford Modular engine#Boss 302 (Road Runner) Variant, have 50% more power and torque than their 1969-70 ancestors, while simultaneously enjoying superior fuel economy and exhaust emissions performance.

In spite of the advance in performance seen in the most recent generation of Boss 302 engines, the original Cleveland-Boss engine had striking performance for its time, and even today would afford ample power in high-performance automotive applications. Because of its historical significance and its ongoing appeal (the Cleveland-Boss engine remains highly sought after, as are the 1969-70 Boss 302 cars, in the enthusiast marketplace), the balance of this article will explore the original Boss 302 engine of 1969-70 in depth, and it will be referred to as the Boss 302 engine. For details about the modern Coyote-Boss engine, see the Wikipedia article "Ford Modular engine".

The Boss 302 engine is a high-performance small-block V8 from Ford Motor Company. This engine powered the Boss 302 Mustang of 1969-70, but new engines of identical displacement and valvegear design—and higher output—are available (see below).

The Boss 302 engine was a hybrid of small-block Ford V8s: it used the block of the small Ford Windsor engine and the heads of the larger Ford Cleveland engine. It was created for the SCCA's Trans-Am road racing series, and was fitted to the factory-made Boss 302 Mustangs of 1969-70.

The high nickel content block has a thicker deck, cylinder walls and beefy 4-bolt main caps. It is identified by screw in freeze plugs on the side of the block, pent roof valve covers, wide heads and a wide intake manifold. A Boss 302 has 8 valve cover bolts (because of the Cleveland heads) as opposed to the standard 302 having 6. The connecting rods are heavy, high strength steel forgings made for high rpm use. The crankshaft is a cross drilled high strength steel forging. The cam and lifters are high lift solid mechanical units.

The wide and large port Cleveland-style heads with staggered valve placement give the Boss 302 high power capabilities. Early units were typically characterized by very large intake and exhaust valves sitting in a small quench style combustion chamber.

The motor has a unique sound as a result of its solid lifter configuration. At idle, properly tuned, the engine has a great deal of 'chatter.'

The power output on this engine competes very well with other high performance smallblocks, like the Chevy 302, the Chrysler 340, and AMC 360.

The original designer, Larry Shinoda, came up with the Boss moniker as a way to pay homage to Bunkie Knudsen, the CEO at Ford and an outspoken proponent of the car's development. He just called him "Boss," he didn't call him "Mr. Knudsen," he was the Boss. So when he told his designers, "I want to design a car that's the coolest mustang out there. I don't want somebody else's name on it, like a Shelby, " so they call it the Boss mustang, because they designed it for the new boss.

This engine was also available on a limited basis in the Mercury Cougar Eliminator.