I cannot find any information on this part number.  I was under the impression that the only 1.54 ratio rockers were part number ECZ 6564.  Stumbled across a post by Ted that mentioned using a drill bit to check the ratio.  The 1.43 ratio will fit a 5/16 bit, 1.54 will not fit a 1/4 bit between the adjuster and the rocker body.  Went through a pile (8) shafts of grungy rockers that I have.  These EAN rockers have a jam nut, with the part number upside down on the rocker (except one that is right side up and larger script).  Cannot fit a 1/4 bit between the adjuster and the rocker body.  

Paul