Gear driven camshafts typically have a higher initial expense as in addition to the camshafts themselves gears and installation kits are required. As gear driven camshafts require almost perfect crank run out typically their installation also requires bottom end servicing. Gear driven camshafts also require greater valve timing accuracy due to the precision required for their use. With this said, if initial cost and valve train noise are not part of your decision process, gear driven camshafts do offer the highest level of reliability and are often utilized in higher displacement engines for this very reason.
The 640 cams are designed for engines of 95 inch or more with compression ratios between 10.5:1 and 11.5:1 used in S&S 124 inch engines.
For technical camshaft information along with detailed product support, please visit our Performance Cams page.