5.0 Mustang & Super FordsHow To Engine
Sleeper LX Comp Cams Camshaft Installation
Adding A Comp Cams Grind To Shake Up A Sleeper
Step By StepView Photo Gallery
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.
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.