I thought EAN prefix meant 1.4 ratio rockers?

Shows what I know! I just assumed the 6564 number covered all high ratio rockers

You're OK, just trying to help ...

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I’ve got someone local that has extra NOS rockers and wants to send you one.  Do you have the friction style or the locking nut style?  Send me your mailing address and I’ll forward that information to that person so they can mail a rocker to you.  My email address is located under ‘Contact Us’ at www.eatonbalancing.com .

Lorena, Texas (South of Waco)

EAN is an Assembly/Engineering/Service PN Prefix.

It identifies when it was first used and when/where used with proper cataloging.

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EAN rockers are 1.43 ratio rockers.  The ECG  rockers are the 1.54, either lock nut (A2) or interference (B-2)





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

So the saga continues. With Ted's help another member of this site was generous enough to try to send me the rocker arm I need only to be foiled by the ineptitude of our U.S Pistal Service. Yes the envelope arrived tracking number and all but EMPTY! The shipping envelope had opened in transport and they delivered an empty envelope! Maybe this is just not meant to be. Mike

Mike, still lovin his 57 t'bird after 53 years!

EAN rockers are 1.43 ratio rockers.  The ECG  rockers are the 1.54, either lock nut (A2) or interference (B-2)

Someone who actually has an ECG-6564-A2  rocker arm needs to measure the OL and drill bit size as described by Ted to nail this down. I think A2 is going to be 1.43 while the B2 is 1.54.

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If that's the case, then the article in Y Block Magazine is wrong.  The later 1.43 rockers (after 58 I guess) started with or had  575





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

If that's the case, then the article in Y Block Magazine is wrong.  The later 1.43 rockers (after 58 I guess) started with or had  575

I am not privy to the magazine and cannot read that tech article.

What I am going by is that during the 1956 production run, a lot of modifying was done on the valve-train. It seems to be around when FORD  put the 312 in the PASS CAR. One was the change in rocker arm ratio and adjustment screw design.

Going by SERVICE PN only in the period MPC and chassis catalogs, the first PN was B6A 6564-A and the later B6A 6564-C. The MPC also shows the B6A-A was the service replacement for the 54/55 EAN which is 1.43. The late 56 and 57 engine had the 1.54 ratio and the ratio went back to 1.43 in 1958.

The seven numeric character you see on the later arms are part of a PN System used briefly 1958/59. The Service PN was changed again in 1960 (C0AZ 6564-A) which was a 1.43 retro-fit for all FYB.

Without the SERVICE BULLETINS and PRODUCTION LETTERS of the period most info is incomplete and/or conjecture. This is also why one engine will have a multi-use of rocker designs on it.

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