2003 Ford Mustang Cobra Upgrades To Crowers Cams

With the baseline power numbers generated with the stock Cobra cams, it was time to install the Crower combo. Given that our test subject was a modified supercharged street Cobra, we selected the Stage 2 (PN 62822-4) designed specifically for supercharged applications. The Crower Stage 2 cams offered 222 degrees of both intake and exhaust duration at .050 along with .475 lift. This compares to a 186/194 duration split and .392/.390 lift split for the factory 4V cams (according to literature supplied by Crower).

Obviously, installation of the cams was somewhat more difficult than your typical 5.0 Ford, but remember the Mod motor DOHC cams are located on the top of the motor rather than tucked down into the belly like a 302. It is necessary to remove the valve covers, front cover and damper for access to the primary and secondary timing chains and care must be taken when removing the stock cams. The proper spring compressor must be used to remove the rockers lest cam tower deflection rear its ugly head (the author speaks from experience here). The Crower cams went in without a hitch and it was off to the dyno again.

The supercharged 4.6 was run once again on the DynoJet in the same configuration, with the only change being the installation of the Crower cams. The data logging indicated a slight drop in boost with the cams--always a good sign that efficiency has improved. The cams made enough of a difference that minor tuning was necessary to duplicate the 11.7:1 air/fuel ratio curve achieved with the stock cams. Once thus tuned, the power output of the supercharged Cobra motor increased to 681 hp while the torque peak jumped to a 690 lb-ft. Measured peak-to-peak, the Crower cams improved the power output by 33 hp and torque by 23 lb-ft.

As a testament to the effectiveness of the cam profiles, the power output improved across the board, from 3,000 to 6,200 rpm. The torque production with the Crower cams exceeded 600 lb-ft all the way past 5,900 rpm (a gain of 400 rpm over the stock cams). Even way out at 6,800 rpm, the Crower cams allowed the motor to produce 656 hp.

I guess it is safe to say that there is power to be had by changing the factory '03-04 Cobra cams.

Replacing the stock cams with (in this case slightly) wilder cam timing can be worth additional power. Often as not, the extra power gain somewhere in the curve is offset by a power loss elsewhere in the curve. Fortunately for Cobra enthusiasts, installation of the Crower Stage 2 cams in our test motor suffered no such trade off. The power improved from 2,900 (the lowest test speed) to 6,800 rpm. Peak-to-peak the gain measured 33 hp, but the Crower cams offered a measurable power gain across the board.

While we had such an impressive test motor at our disposal, we decided to take the guys at Kenne Bell up on their offer to test a new '03-up Cobra blower upgrade. The standard Cobra blower upgrade comes with a 422 twin-screw (Autorotor) blower. Capable of serious power (we've made well over 600-wheel hp), the 422 blower is head and shoulders better than the stock Eaton in terms of power potential.

Like any good force-fed Ford fanatic, the gang at Kenne Bell knew that even though the 422 represented a huge leap in performance over the stock blower, there will always be enthusiasts looking for that much more. It was for these enthusiasts that Kenne Bell designed the 424 blower upgrade for the '03 (and later) Cobras. Capable of even more power than the 422, we decided to see just what the larger 424 was capable of.

After running Crower cams and the 422 blower, the guys at Kenne Bell swapped out the 422 and installed the larger 424 blower upgrade. The upgraded blower was installed with the same pulley combination used on the 422 (9.25-inch crank and 3.0-inch blower). The Accufab inlet and throttle body we retained, as was the 90mm mass-air meter and Kenne Bell cold-air intake system.

Swapping on the larger blower upped the maximum boost pressure from 25.6 to 29.6 psi helping the peak power jump to the magical 700 mark. Once again, the torque production was now beyond impressive, with the supercharged Cobra now thumping out and incredible 749 lb-ft at 4,100 rpm and over 700 lb-ft from 2,900 to 4,900 rpm. According to Kenne Bell, there was still over 2.5 inches of vacuum present in the intake tract, meaning there was a restriction somewhere at this elevated power level. They felt that possibly a larger throttle body or further revisions to the throttle body entry may free up some additional power at this boost level.

Equipped with the Crower cams and 424 blower upgrade this (street driven) supercharged Cobra (weighing a portly 3,780 pounds with driver) managed to rip off a best of 10.19 at 142 miles per hour. Pretty impressive numbers from a full-dress Cobra.