Quote:
Originally Posted by J Franklin
I guess it boils down to if you are working on a race engine, B, or A engine, follow the book or the shop that rebuilt it. It's all your choice.
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Partially true.
ALL modern solid lifter common engine cams are designed with a clearance ramp.
Most vintage cams such as the model A/B were designed by the 3 curve method. These have a concentric base circle.(no clearance ramp) The running clearance was originally specified by trial and error. .016 seemed to be adequate for long valve life and low noise.
As a side note, modern HYDRAULIC lifter cams have a concentric base circle also.