September 14, 2005

Formula For Success
Engine building isn't always just about engine building; it's also about choosing the right parts. Building a healthy street Cleveland involves choosing the right heads and induction system, which is key with the 351C. Choose a single-plane manifold and 4V heads with a 351-inch bottom end, and you can forget low-end torque. A single-plane manifold with 4V heads makes its power at high rpm. And that means peak torque around 6,000 rpm, not at 3,500 rpm where you need it most on the street.

The 351C-2V head is more appropriate for street use because it has smaller ports and valves, which moves peak torque down where we need it most: at 3,500 rpm. Choosing the right camshaft profile and dual-plane intake manifold improves driveability tenfold. Torque comes on crispy and strong as the engine spins through 2,500-4,000 rpm. The downside to the common U.S.-built 351C-2V head is its wide-mouth open chamber. You get good quench with this chamber, but lousy dynamics because it tends to create two flame fronts under hard acceleration, which causes spark knock (pinging).

The best Cleveland head on the planet is the Australian 351C, with the best combination of ports and chambers: the 351-4V wedge chamber and the 351C-2V ports for better low and midrange torque. PowerHeads is your source for the Aussie Cleveland heads, which are supplied ported and fitted with hardened exhaust valve seats. It's the perfect Cleveland street head.

Speed-O-Motive builds its 351C much the same way it does small-block 289/302s. Oil galleries get a workout where necessary. Oil return flow is improved to ensure sufficient oil in the pan. Press-in oil gallery plugs are tossed in favor of screw-in plugs.