Early Winston Cup Lobe Profile

2/28/2024

Here is the profile graph and the model milling lift table for a popular NASCAR Winston Cup lobe profile we designed in the 1980's. This would be "top secret" stuff at the time. This is considered an old design compared to the lobe designs of today. It is an asymmetrical flat tappet lobe with a rate designed for high RPM and endurance. It has easy ramps with a running lash of .012 for rocker ratios of 1.5 or 1.6. It was designed with our software program for the 0.874 diameter flat tappets and valve springs used at the time. A lobe profile design today would probably dwell the maximum velocity on the opening and closing sides of the lobe. Different ramp designs would probably also be used. Today's lobe design would have more area with the same duration numbers at .020 and .050 and the same lift. The duration numbers at .100, .200, and .300 would be larger. The larger area is the major difference between a new lobe design and an old lobe design. Lighter and stronger valve train components make it possible to design lobe profiles with faster rates and more area. Camshafts with larger journal diameters are also an advantage. It would be interesting to analyze the NASCAR camshaft lobes of the 1960's and 70's. You need to know where you've been to know where to go.

Profile available for the MS-DOS Reed program.