Michael Johnson
Technical Editor
April 1, 2001
Photos By: Chuck James

Step By Step

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138_02z Ford_mustang_lx Engine_view
“What? No pulleys?” Mark Mainiero of Unlimited Performance always gives us a hard time about our Sleeper LX not having underdrive pulleys on it yet. On our next visit to Unlimited’s shop, maybe we’ll let him not only install pulleys, but also possibly a high-flow X-pipe. However, for now our underhood area still looks stock, stock, stock. With the mild idle of our new Comp Cams Xtreme Energy roller cam, no one will know we have added a cam unless we tell them. (Let’s keep it our little secret.)
138_03z Ford_mustang_lx Engine_view
Getting to the heart of the matter, Mark removed the upper intake, valve covers, the timing cover/water pump assembly, and the timing chain. He places a paper towel over the front of the oil pan to keep debris out.
In our February 2001 issue (Speed Lust, p. 14), we showed you Anderson Ford Motorsport’s new Tappet Tools. Attached to the bottom of the threaded bolt is a magnet that latches onto the lifter and pulls it up away from the cam. This allows the removal of the cam without taking the lower intake off and saves at least a couple hours of labor in the process. This article gave us the perfect opportunity to put them to the test. Yes, like us, Mark was skeptical, but he was willing to play along.
138_05z Ford_mustang_lx Engine_view
With the valvetrain removed, insert the tappet tool into the pushrod hole until you feel it connect to the lifter. Using the head of the tappet tool, turn it until you feel the lifter come in contact with the bottom of the head. At this point the lifter should clear the cam upon removal. Go one cylinder at a time, and go back over every cylinder before removing the cam.
138_06z Ford_mustang_lx Valvetrain
This is how the tappet tools should look prior to removing the cam. You don’t want to have any jerking motions when using the tappet tools; take your time and be deliberate in your actions when attaching them. And remember—remove the cam slowly in case you do come in contact with a lifter.
138_07z Ford_mustang_lx Engine_view
To our surprise and relief, the tappet tools worked great in helping remove the cam. Here Mark is installing our new cam just as slowly as he removed the old one. He installs the cam straight up because the Comp Cams Xtreme line features a 4-degree advance ground in.
138_08z Ford_mustang_lx Timing_chain
Along with a new cam, we also got a new timing chain from Comp Cams. We were certain that with almost 120,000 miles on it, our old one was a little tired.
138_09z Ford_mustang_lx Timing_cover
Don’t forget to retighten the lower timing cover bolts. You’ll surely have a mess if you don’t.
138_10z Ford_mustang_lx Engine_view
We can now reinstall the front acces-sory components we removed in the swap process.
138_11z Ford_mustang_lx Fuel_pressure_regulator
We also installed a Kirban fuel-pressure regulator during the cam-swap process. This new design from Kirban features 100-percent billet-aluminum construction. The regulator will allow us to tweak the fuel pressure to the engine’s liking. Kirban doesn’t sell direct, but several of our advertisers should be able to supply you with one. Check the ads in 5.0&SF to see who carries it.
138_50z Ford_mustang_lx Engine_view
Finally, Mark reinstalls the valve covers, the upper intake, the spark-plug wires, the air intake hose, and all electrical connections.

In our Dec. 2000 issue ("Power Napping," p. 71) we began the arduous task of building a 5.0 Mustang sleeper. Instead of adding parts that would give away our lust for speed, we chose components and techniques that would give us power without the look-at-me neon sign.

We began by adding Power Heads' CNC-ported stock heads, Extrude Honed Holley SysteMAX lower and stock upper intakes, BBK headers and a 65mm throttle body, and Comp Cams' roller rockers and replacement lifters. The headers and the throttle body were the only giveaways, but most people have those on otherwise-stock 5.0s so we thought we could get away with adding them. When all was said and done, we ended up with 238 hp and 291 lb-ft of torque with nice midrange power.

As we stated in the December article, we wanted to return to Unlimited Performance in Lake Worth, Florida, to try a few other tricks to make the car run even harder without drawing unnecessary attention. First up on our list was to try a cam. With our combo we can't add a massive cam, so there won't be that telltale lumpity-lump sound emanating from the exhaust. No one will know we added a cam unless we tell them (no, it's all stock--trust us).

We knew a cam would be of great benefit to our Sleeper LX, so we contacted Comp Cams. A few days later we received one of its Xtreme Energy O.E. roller camshaft grinds (PN 35-324-8). This grind features a gross intake and exhaust valve lift of 0.544, 270 (intake) and 276 (exhaust) degrees duration at 0.006 tappet lift, 218 (intake) and 224 (exhaust) duration at 0.050 lift, with a lobe separation of 112 degrees. This cam is perfect for our combo. It was designed for a 5.0 with mild modifications, 3.27-3.73 gears, a larger-than-stock throttle body and mass air, good heads, and a manifold. Aside from our car having 2.73 gears, the specs were right in line of what we're running. We're also still running a stock mass air meter, which doesn't seem to be hanging us up at this point.

Everything we previously added was still in place with no other changes except for the cam. We wanted to try a set of Comp Cams' performance valvesprings, but we were unable to do so because of the Power Heads exhaust valve-seal design. The inner spring would have torn up the valve seal and made our car burn oil. We wanted to try a set of springs as well because before we added the cam, horsepower dropped significantly after 5,000 rpm. We wondered if a set of springs would help the problem. We didn't experience the same dropoff with the new cam, but we would still like to test that theory before we add a ZEX nitrous kit.

In the meantime, even with 2.73 gears the car feels great, and we haven't even added pulleys or a high-flow X-pipe yet. With the installation of the cam we're at 244 hp and 297 lb-ft or torque. The power band of the cam is gradual with a nice horsepower curve, and the power really builds as the rpm climbs. The cam also has excellent driveability characteristics with just the slightest lope at idle. If we can get the car to make in the neighborhood of 260 hp before we add the laughing gas, we'll be happy.

Horse Sense:
Duration is the number of degrees in crankshaft rotation that the valves stay open. To simplify the concept even further, it's basically how long the valves stay open. Duration plays a huge part in the design of a cam, because it is a major influence on how much air gets into and out of an engine.