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

EAN's are supposed to be 1.43 rockers and yes, have  a lock nut.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

No luck.  Broke the shafts down, and put a micrometer to  the rockers.  They are the 1.43 ratio.

Paul

JFYI -

EAN-6564-B1 was the ENGINEERING PN for the 1954 to mid 1956 rocker arm (1.43), when FORD changed the ratio in mid-56 production (1.54). FORD then went back to 1.43 ration with the 1958 model run (FYB HP was over). The SERVICE PN was upgraded to C0AZ 6564-A. 58/59 rocker arms had the PN/CASTING ID used by FORD during 58/59 consisting of seven numeric characters.

Not too sure when FORD dropped 1.54 service replacement rocker arms but this is why you will see assemblies with mixed ratios.

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