Most cams available on the market for air cooled Porsche race engines have been developed to work best with the port shapes derived from stock Porsche cylinder head ports. When using Elite’s RSR, SC, GT-2 and 962 cylinder heads, traditional cams will work as expected. However, when using Elite heads which have the “HD” and “N” family of high velocity/low volume ports, it is imperative that you use an EESL cam with the lobe dimensions necessary to harness the full potential of these ports. Again, if you are planning to purchase Elite heads with our “HD” or “N” family of ports, we cannot emphasize enough the importance of using one of our cam profiles developed specifically for these applications. The awesome results will justify this additional step!