Michael Johnson Associate Editor
June 1, 2003

Horse Sense:
In an earlier test conducted by Panhandle Performance, the SysteMAX II intake outshined many other top-name intakes on the market. We featured that test in our Sept. '01 issue ("Balancing Act," p. 69), using Tech Editor Houlahan's 347 stroker as the guinea pig. His engine topped out at 433 hp and 431 lb-ft of torque on an engine dyno. Needless to say, we're hoping to improve on those numbers with our 349 stroker.

When we last left our 349 short-block at Panhandle Performance in Lynn Haven, Florida, it had been stuffed with a Lunati stroker kit's crank, rods, and pistons. Everything was looking good, and we couldn't wait to get back and witness the installation of the Lunati camshaft and Holley SysteMAX heads and intake.

While Panhandle's Mark Biddle had planned to order a custom cam, he found an off-the-shelf grind that he liked just as well in Lunati's 51099 camshaft. With a 112-degree lobe center, our cam utilizes a split-duration pattern with 228-degree intake and 238-degree exhaust duration specs. Installed at 1 degree advanced, the intake centerline is actually at 111 degrees. The camshaft sports an actual lift of 0.576 intake and 0.544 exhaust. Mark says this cam should reward us with good street manners yet provide nice power up top with our long-runner SysteMAX II intake. Furthermore, Mark split the duration at 0.050, a little more toward the exhaust in anticipation of a small shot of nitrous and for a little more extra power at high rpm than if the cam was a single-pattern grind.

Mark and his partner, Adam Day, were pleasantly surprised at the flow numbers they were able to get from the Holley SysteMAX heads. Panhandle hasn't had much experience with the 17-degree heads but was impressed with the results. Adam treated our heads to a Stage III port and polish job that included full intake, exhaust, and combustion-chamber porting, and Panhandle's competition valve job. The Holley heads were supplied with Ferrea EV-8 stainless 2.02/1.60 valves, chrome-moly retainers, and 0.600-inch dual-lift springs. Panhandle used different locks and seals, and changed the inner valvesprings for a better fit and more spring pressure.

Panhandle also treated our Holley SysteMAX II intake to a port job. A Stage II porting brought the average runner flow up to 317 cfm. As is usually the case, the No. 5 cylinder had the lowest flow number at 308 cfm, while No. 8 boasted the highest at 324 cfm. Well, enough numbers-let's put this thing together.

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Cam Specs

Duration at 0.050:228-degree intake, 238-degree exhaust
Lobe Center:112 degrees
Installed At: 111 degrees (1-degree advanced)
Lobe Lift:0.335-0.340
Rocker Arm Ratio:1.72 intake, 1.6 exhaust
Actual Lift:0.576-0.544

Flow Data at 28 Inches

Valve LiftIntake
0.100 67 5480%
0.200 142 10675%
0.300 200 15276%
0.400 236 19080%
0.500 273 21077%
0.600 292 22577%

Port Size Matters
When determining what heads to add to your Mustang, it's a good idea to keep the head's port size in mind. Panhandle's Mark Biddle advises to try and size the intake port to the displacement and the rpm range of the engine, with a stronger emphasis on the displacement of the engine you're building. For a 302 engine, a 160-170cc intake port is favorable for a hydraulic-roller-cammed engine. For our 349, Mark says a port size from 175 to 200 cc is ideal. Panhandle goes in and velocity-probes the intake and exhaust ports-the higher airflow areas are where the company starts its mods. That way, Panhandle minimizes the material removed, but it maximizes the flow through the area of the head that has a high port velocity. After porting the heads, the size of the port increased to 175 cc, which is fairly small for the amount of airflow the port now offers. The high-flowing small port will make great torque for our street-based engine.

When talking about flow numbers, Mark says our 349 stroker needs a head capable of flowing around 275-295 cfm. Low lift numbers are even more important on hydraulic-cam applications, and Panhandle concentrates on maximizing those as well.

Once our heads received porting work, they fit perfectly within these numbers. Furthermore, Mark prefers to have an intake/exhaust flow ratio of 75-80 percent. In other words, the exhaust flow number should be within 75-80 percent of its opposing intake flow figure.

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