What does it take to transform a 1998 Cobra into a 2004 Cobra Terminator? Patience, planning, sunscreen, and a whole lot of beer. This series chronicles the swap, modifications, and tuning required to create the ultimate sleeper.

2004 Cobra Conversion

We love our 1998 Cobra. When new – it represented a new direction of performance for the Mustang. By 1998, most of the hand wringing about the demise of the pushrod 5.0 liter had subsided from the Mustang community, and enthusiasts were beginning to see the potential of the 4-valve modular motor. Over 300 horsepower and a high revving redline dawned a new age for the Pony car.

By 2003, Ford decided to increase the potency of the Snake’s bite – not through increased displacement, but with forced induction. The masses were sold, and so were we. Since the introduction of the platform code named “Terminator,” we’ve kept an eye out for a donor vehicle we could use to create our own Terminator. In the Spring of 2006 our wait was officially over.

The 2003-2004 SVT Cobra used an iron 4.6 liter block, dual overhead cams, a cautious 8.5:1 compression ratio, and a whipple supercharger to create and estimate 390 factory horsepower, and 390 lbs of torque. This power was fed through the T56 – six speed transmission to a 3.55:1 final drive independent rear. The aftermarket stepped up immediately to provide user-friendly modifications to increase boost, and decrease air charge temperatures. The Terminator became an easy to modify, tire shredding monster almost over night.

Our goal for the 2004 – Cobra/Terminator swap was to retain all of the driving characteristics we loved about the 1998 Cobra, while adding the well mannered, raw power of the 2004 Cobra. We wanted reliable horsepower that could be flogged on the road course lap-after-lap without concern for timing, fuel, or detonation. During the project – we changed our plans more than once, but throughout all the trials and tests – we learned one important thing: We’d do it again in a second.

We’ll detail this project with several upcoming installments:

• 1998 VS 2004
• Preparation –Planning the swap
• Wiring Harness & Additional Components.
• The Swap
• Intercooler
• Fuel
• Tuning
• On the Track

Photo: We sourced our 2004 Cobra motor and T-56 transmission from an unfortunate donor that had only 14,000 miles on the odometer before meeting a telephone pole. The chassis from the donor car was a complete loss, but as you’ll see, we were able to source a LOT of the components from the original 2004.

Photo: The T-56 from the 2004 Cobra is a horsepower hungry, six-speed. Ratios are: 2.66 - 1^st, 1.78 – 2^nd, 1.30 – 3^rd, 1.00 – 4^th, 0.80 – 5^th, and 0.63 – 6th.

Photo: We sourced the engine wiring harness from our donor. The initial plan is to add only what we need to make the 2004 work just like it did from the factory. As you’ll see, that presents several challenges in the 1998 Cobra chassis.