Pete Epple Technical Editor
April 1, 2010

An internal combustion engine is essentially an air pump, hence, the amount of power an engine produces is based on how much air you can efficiently move through it. Although intake manifolds, cylinder heads, and exhaust systems play a very important part, without a way to control airflow in and out of the cylinders, they are rendered useless.

Camshafts play a huge role when it comes to making power. When it all boils down, the camshaft(s) orchestrate a symphony of valvetrain components that allow the air/fuel mixture in, and spent exhaust gasses out. Camshafts are measured in a few different areas-lift, duration, lobe separation angle, and intake and exhaust centerlines. Each specification helps to make up a cam profile. Though we could go on for days about everything that makes a cam work, for this story we are going to stick to the basics.

Lift is probably the most commonly known measurement when talking about a camshaft. It's simply how far the cam allows the valve to rise off the valve seat.

Duration is the measurement of how long the valve remains off the seat. Duration will tend to dictate an engine's personality. If the valves stay open for a longer period of time, overlap generally increases, which is good for high-rpm power but bad for emissions and idle quality. Overlap is when both the intake and exhaust valves are open simultaneously, and is another way engine builders can improve scavenging.

Lobe separation angle (LSA) is the distance between an intake lobe and exhaust lobe at its respective max lift point. LSA is directly related to overlap and also helps with scavenging. If a camshaft has a wider LSA (higher numerical number), there will be less overlap. This offers more idle vacuum because there is less cylinder pressure bleed off as the piston approaches BDC. As the LSA tightens (lower numerical number), intake manifold vacuum will be decreased.

Intake and exhaust centerlines are ground into the camshaft as initial timing points, and give engines builders the ability to degree the camshaft(s) to the rotating assembly.

The Hardware
To put this camshaft theory into practice, we headed to Blow-By Racing (BBR) in Boca Raton, Florida, where Chris Jones and Matt Frith were preparing to swap camshafts in BBR's 2010 Mustang GT.

BBR's Billet Stage 1 camshafts are a considerable step up from the stock sticks. "We designed the BBR Stage 1 cams to be as aggressive as possible without having to change valvesprings," explains Jones. This speeds the install time and saves the customer money, yet provides a nice upgrade over stock in power and sound quality.

"On a stock Three-Valve Mustang, valvespring coil-bind occurs at 0.512-inch lift. Our Stage 1 cams have 0.480-inch lift. The other benefit of our Stage 1 cams is that they are designed to take advantage of the Variable Cam Timing from the factory."

With the stock cams checking in at 0.439/0.439-inch lift, the 0.480/0.480-inch lift BBR cams are a healthy improvement. Lift isn't the only area where BBR has made improvements. Duration has been bumped from 196/221 degrees at 0.050-inch lift to 227/233 at 0.050, and the LSA went from 115.5 degrees with the stock cams to 114 with BBR's Stage 1s.

Matt Frith, affectionately known around the shop as Googli Bear, started by strapping the Mustang to BBR's in-house Dynojet for baseline numbers. After a few quick pulls, the GT laid down 306 rwhp and 323 lb-ft of torque, and we headed to the track. After a few passes down the strip at Palm Beach International Raceway (PBIR), in Jupiter, Florida, Jones got the launch down and the Mustang clicked off consistent mid-13-second e.t.'s, with a best of 13.55 at over 104 mph.

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