Not everything went perfectly. After the exhaust was finished and dialed in, while showing off the car, the passenger-side exhaust was damaged, forcing Willjo to pivot and install a Bassani 3" catback system. Despite the setback, the tuning with Lund was completed, and the car ran impressively.
On the dyno, the transformation was undeniable. Here’s how the two setups compared:
Original 4.6L
- 291.2 horsepower @ 6,100 RPM
- 290.4 lb-ft of torque @ 4,400 RPM
Gen 3 5.0L Coyote
- 478.4 horsepower @ 6,600 RPM
- 414.2 lb-ft of torque @ 4,500 RPM
The Gen 3 Coyote didn’t just outperform the original setup; it delivered the highest naturally aspirated rear-wheel torque of any Coyote tested on the LMR dyno!
Willjo reflects on the challenges posed by the digital throttle body, tight clearances, and wiring complexities, which were obstacles but were overcome with persistence and ingenuity. The original T45 transmission didn’t last long under the new power, leading to an upgrade to a T56 from a 2003 Cobra model with 53,000 miles, a near-perfect match for the car’s newfound capabilities.
Final Thoughts & Was It Worth It?
Willjo emphasized patience, preparation, and flexibility. A few unexpected issues arose, but the project showcased the importance of problem-solving and persistence. His Cobra is now a testament to personal vision, dedication, and performance: a naturally aspirated powerhouse, finely tuned, and ready for HPDE events and track days.
As Willjo puts it, the project is as much about creativity and customization as it is about raw horsepower. From start to finish, this swap represents a masterclass in meticulous planning, hands-on problem solving, and automotive passion!
From a worn but dependable 338,000-mile 4.6L to a modern Gen 3 5.0L Coyote delivering nearly 500 wheel horsepower, Willjo’s 1999 Cobra is proof that with patience, skill, determination, and vision, even the most ambitious swaps can become a reality.
