CASTING ID NO 5751066 (1.43 ratio) was introduced in the 1958 model year (used to 1964) and eventually became the service replacement for all prior years incl the 1.54 ratio arms.

The SERVICE PN was C0AZ 6564-A.

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Thanks. So these should be for 55 and later Y Block 272-292? They look new unused in Picture. No Idea how long they have been sitting but the Price is right if they are New. Seller has no clue what they are for. Maybe bargain Time.

  

Yes, that is what the casting number is. I have a set of rockers from my 64 F100 from when I purchased it 14 years ago. I'm sure they are not the same assemblies from 1964 but they all are cast with 5751066. I will admit the last digit "6" on some does look like an 8 and they are 1:43 ratio. 

64F100 57FAIRLANE500

Could the CASTING ID NO possibly be 5751066?

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Casting # on the Arms is 5751068. Anybody know what these are for by Application? Thanks

  

Can you post a photo? 

I know that EBU connecting rods are the longer rods used on 272 and 292 engines. The shorter ECZ rods are for 312s. Maybe the same applies to rocker arms. 

So they are 272 292 312 Rocker Assemblies? Look like NOS. Thanks

  

They probably are "EAN", not "EAU." EAN rocker arms are 1.43 ratio. 

There are "EAU" rocker arms; the "EAN" listed on John's site (ford-y-block.com) could be a misprint. 

What ratio are you looking for? The 1.43-ratio rocker arms are pretty common. Rather than buying a used set that needs to be rebuilt, you probably buy a rebuild set from Tim McMaster or a new set from John Mummert. Rocker Arms Unlimited in Redding, CA is another option. 

There is a listing on local Market Place for a Pair of complete Rocker Arm Assemblies. Seller has no Idea what they fit and no ID Number. Arms have casting # EAU. Any Idea what they are? Look like Y-Block shaft Assemblies from Picture.