Dr Jamie Meyer
August 1, 2005

Horse Sense:
This is not a modification for the faint of heart. Once you start taking a Four-Valve, four-cam modular small-block apart, you'll think that the parts will never go back together. Unless you want to get involved in a serious weekend project, we suggest that you leave this one to the pros.

So, you got yourself an '03-'04 SVT Cobra-the baddest Mustang ever produced-and you've done the simple things like a cold-air intake, performance exhaust, and pullied the supercharger to make more boost. Maybe you have even had Apten Performance (run by MD Motorsports) port your stock blower for a stealthy extra 30-40 rwhp. Top that off with a set of drag radials and a nice reflash of the computer, and you've got yourself a mid-11-second car that will drive anywhere in the country with complete reliability and comfort. What do you do now?

Well, you could add an aftermarket supercharger and get right into the 600-plus-horsepower range at the wheels, but as soon as you lift your hood everyone in the game is going to know exactly what you've got. Perhaps a better way to get that extra edge on the competition is to look underneath those massive cam covers to see if you can extract some power with aftermarket camshafts. For quite some time, we've been told that camshafts for these cars were coming that could make a big difference in the performance of the already overachieving blown Four-Valve. But, it wasn't until we started talking with Dennis Miles of Comp Cams that we realized just how serious this cam manufacturer was about getting more power from the most powerful Ford engine ever assembled.

"There's always a lot Comp Cams can do over the factory valvetrain," Dennis explains. "These cams are designed for a blower or nitrous car-not a turbo car though, because they can over-scavenge the combustion chamber. The goals of these cars is to get the exhaust out as quickly as possible. These Ford modular heads flow extremely big numbers-they are efficient cylinder heads-so we wanted to design camshafts that would get all of the exhaust out of the head. With this lobe separation, these cams can easily help on cars that make up to 30 pounds of boost."

Of course, the cams (PN 106360; $1,431.24) come in a set of four with the intake and exhaust profiles on separate cams. They spec out with intake numbers of 0.475-lift, advertised duration of 265 degrees, and actual duration of 230 at 0.050. On the exhaust side, they measure 0.450-inch lift, advertised duration of 267 degrees, and actual duration of 323 at 0.050. The Comp Cams cams are set up for a 116-degree lobe separation for low overlap and decreased chop for a smooth idle. For comparison, the stock cams are 0.394-inch lift for both the intake and exhaust with 184 degrees of duration at 0.050 on the intake and 194 degrees on the exhaust.

We also highly recommend that when you buy your Comp Cams Cobra camshafts, you invest in its springs (PN 26123-32; $503.36) and its retainers (PN 799-32; $133.12). Please note that Comp Cams has 10 other Four-Valve modular-specific grinds available, and if you go with its cams that are over 0.500-inch lift, you will need different springs and retainers. Most of its other cams are for larger boost or turbocharged applications, and it is possible to mix and match intake and exhaust cams for your application. Of course, they can custom-grind cams if you want to design a set for your particular application. Remember, you can always move your centerline with a set of custom cam gears on the front of the engine.

As for the rpm range with these cams, Dennis tells us, "It'll vary from car to car, but we state that the cams are designed to work from 1,500-6,000 rpm. I wanted to be a little conservative with that because each car will vary. I didn't want to promise 6,500 rpm if not all the applications will see that rpm."

Generally, these cams were designed to enhance what the SVT engineers have already provided you with. They will make good power all over, but they will sparkle on the top end. With blown Cobras already owning the streets, we couldn't wait to see what one would run like with a set of these hot new cams stuffed into those massive cylinder heads. Our only chore left was to find the right car and the right shop for the installation and testing.

Only on the market for a month or two when they arrived at our offices, we were really jacked up to see what these Cobra cams could do. Luckily, we have access to MD Motorsports in Cincinnati, Ohio, who caters to hoards of Terminator customers thanks to its Apten-ported stock Eaton supercharger program ("Boost Exchange," May '04 issue). MD Motorsports has now taken over the ported-Eaton business from Apten, and it continues to do a stellar port job on these factory huffers.

Check out our pictures for a look at what it takes to put one of these big motors together. Please note that we did not document every single piece going together, instead we had MD Motorsports mock up each step so we could grab a picture of it for our readers. Installation of any cam into a Four-Valve engine requires more than your average knowledge of Ford small-blocks, some specialized tools, and a little bit of patience.

BaselineComp CamsDifference

Our test car was your typical '03-'04 Cobra, owned by Terry "Beefcake" Reeves. When we baselined the car, it had already benefited from the skills of the folks at MD Motorsports. It was outfitted with an Apten-ported stock Eaton supercharger, 2.8-inch supercharger pulley, a K&N FIPK cold-air intake, UPR off-road exhaust, and a Magnaflow after-cat exhaust system. After a tune at MD Motorsports, the car was base-lined at 480 rwhp and 486 rwtq, and Terry was able to drive the car into the 11.80s at over 120 mph with the help of Nitto 315 Drag Radials. Basically, your typical bolt-on '03-'04 Cobra in search of the next mod to put it over the 500 rwhp mark. We thought our Comp Cams bumpsticks could help-and help they did.

We were curious what the experts had to say about the whole installation procedure, and Brandon had this to say: "The time for install of these cams would vary depending on people, but I would say it's a good two-day project. You have about 18 hours in R&R of the engine, and then however long it takes to install cams and springs in the engine. The cost of just labor for this job would be around $2,100 depending on what other options were on the car and other work required. You will need a valve spring compressor for the overhead cam setup to switch the valve springs-other than that, it is basic hand tools."

Once the installation was complete, MD Motorsports strapped the Beefcake-mobile down to their in-house chassis dyno and got to work on the final tune and evaluation. Baseline numbers on this car were fairly typical of a lightly modified Terminator: 480 hp and 486 lb-ft of torque at the rear wheels. After the cams were installed, those peak numbers shot up to 521 hp (41hp gain) and 500 lb-ft (14 lb-ft gain). The trade-off for those big numbers was only a slight hint of power loss below 3,500 rpm, but from that point on, the Comp Cams stuff just takes off. At 6,500 rpm, the numbers went from 459 hp and 371 lb-ft to 505 hp (46hp gain) and 408 lb-ft (37 lb-ft gain). Even farther up the power band, past the factory redline of 6,500 rpm, the Comp Cams camshafts continued to pay big dividends. At 6,800 rpm, power went from 440 hp and 340 lb-ft to 507 hp (a 67hp gain) and 392 lb-ft (a 52 lb-ft gain). Keep in mind, the graphs have more resolution (data points) than our chart, but seeing both really shows how the mods affect the engine across the rpm range.

The bottom line is that the Comp Cams Four-Valve cam kit makes big, big power on the factory-blown super snake. They move the peak power up 300 rpm and extend the usable rpm range all the way to 7,000 rpm. And, remember that loss of torque (minimal in this case) on a Terminator is a completely different case than on a naturally aspirated car because you have that big supercharger chugging away at the crack of the throttle. So, they make big power, but how does it affect the car on the street?

After spending a few weeks with his pumped up Cobra, we asked Terry about the characteristics of his pride and joy. "The idle is a little louder," he told us. "People definitely know there are cams in there. But, you can't tell a difference with the way it idles around town. Rarely, it will drop a few rpm when you come to a sudden stop, but it's nowhere near stalling. The neatest thing is how different the blower sounds. You can just tell that it is really sucking in the air to fill those big heads now. It sounds kind of like a turbo. Overall, it sounds great, it runs great, and I don't have any problems. Thanks Comp Cams."

These new Comp Cams camshafts look to be a great mod that really deliver on the power without upsetting an otherwise perfect car. We also think that installing cams on these cars is a little sneaky because only a few people will instantly know what you have. As you get used to this power level, it is also important to note that these cams would work great with a bigger supercharger like a Kenne Bell or Whipple.

The only downside that we can see is that this is an expensive modification compared to the other items on our test car. But, like any other hot rod, you soon run out of $100 dollar modifications that give you 20 hp. You will also be without your car for a couple of days.

The best part about all modular Ford engines has always been the cylinder heads. In Two-Valve or especially Four-Valve form, they allow a 281-cubic inch motor to act like one twice that size. Toss in the factory supercharger of an '03-'04 Cobra, and you have the potential for well over 500 rwhp without really affecting the street manners at all. We think that Comp Cams' efforts with this engine family should be applauded, and we can't wait to see what comes out next.

The Missing Rocker
Hmm, that's fun," Brandon said as his examined the rocker lying in the bottom of the head. "I guess we now know why Terry's car has always been down 5-10 horsepower."

As we photographed the reassembly of the engine, lying in the bottom of the passenger side head was what appeared to be an unused factory rocker. If you look closely at the photos you can tell that there isn't a single wear mark on it, suggesting to us that the thing popped off right at initial start up at the factory. We have heard of big-rpm, naturally aspirated Four-Valve modular racers popping rockers on every run, but we had never seen it on a stock Cobra. After a few phone calls, we found that this wasn't the first time that someone had found a rocker in the bottom of the head on an '03-'04 Cobra.

MD Motorsports is planning to develop a regular procedure-using a bore scope no doubt-on all of the Terminators that come through its shop to make sure all the factory valvetrain components are in place. We estimate that this may have cost us at most 5-10 rwhp on the baseline numbers, so factor that into the final numbers if you like.