Single or Dual Pattern Cam
Dan,
A trend today that was not there 20 yrs ago is using lower ratio rockers on the exh side, especially with DP cams. Is that a way of using a cheap DP shelf cam that has too much exh duration, & lower ratio rockers reduce lift & effective duration? Probably.
From Sig Erson of Erson cams,
'The cam with closer lobe centers will always produce more power in the midrange than a cam using the same profile & wide lobe center, & in many applications will produce more power all through the range depending on many variables such as the induction system, rod angularity & flow capacity of the ports.'