“In keeping with the spirit of the original, the new Boss 302 engine achieves its maximum power output at speeds at or above 7,500 rpm,” says Harrison. “Unlike the original engine, however, low-speed torque and driveability are uncompromised thanks to twin independent variable camshaft timing (Ti-VCT) technology and computer-aided engineering design tools.”

Harrison and his team began exploring Boss 302 concepts starting with the engine’s ability to breathe – essential to the production of horsepower. Because credible track performance requires high power production between 5,000 rpm and 7,000 rpm, the team needed a new approach to intake manifold design.

Borrowing from the Ford Daytona Prototype engines, the resulting short-runners-in-the-box design virtually eliminates lag when the throttle is snapped open while producing peak power output at high rpm.

“The effect of the new intake design is dramatic,” says Harrison. “When I took the prototype car to Mustang Chief Engineer Dave Pericak, he took a short drive, tossed me the keys and said ‘Book it…it’s in the program.’ He knew what we were onto, and that’s really the point where the Boss 302 was born.”

To take advantage of the racing intake manifold, cylinder head airflow was fully optimized by CNC porting the entire intake and exhaust port and combustion chamber. The painstaking machining process takes 2.5 hours per head to complete.

To accompany the higher peak-power engine speed, the team had to engineer a lightweight, high-speed valvetrain and bulletproof reciprocating assembly that would not only hold together for 150,000-plus miles but also produce power at peak rpm.

“What most people don’t realize is that engine stresses increase exponentially as engine speeds rise,” explains Harrison. “So moving up from GT’s 7,000 rpm redline required significant re-engineering of many different parts. Sacrificing reliability and usability over the GT engine was never an option.”

Some of the Boss-specific parts contributing to the Boss 302 V8’s output and durability include:

- Revised composite intake system with shorter runners, inspired by Daytona Prototype racing engines, for high-rpm breathing
- Forged aluminum pistons and upgraded sinter-forged connecting rods for improved strength, needed for the higher combustion pressures and engine speeds
- New high-strength aluminum-alloy cylinder heads with fully CNC-machined ports and chambers for exceptional high-rpm airflow without sacrificing low-speed torque
- Lightened valvetrain components to provide excellent dynamic performance up to speeds well above the engine redline
- Sodium-filled exhaust valves for improved heat dissipation
- Race-specification crankshaft main and rod bearings for higher load capability and improved high-speed durability
- 5W50 full-synthetic oil with engine oil cooler for improved oil pressure and longer-lasting lubrication during extreme racing conditions
- Revised oil pan baffling for improved oil control under racing conditions and during cornering loads greater than 1.0 g

- 5W50 full-synthetic oil with engine oil cooler for improved oil pressure and longer-lasting lubrication during extreme racing conditions