Rocker Arm ID Home » Keeping The Dream Alive! » Technical http://forums.y-blocksforever.com/Topic124711.aspx

Print Topic | Close Window

By paul2748 - 9 Years Ago I have a set of rocker arms that the only marking on them is the # 70.  Can any one ID these?  They have the interference fit adjusters. By 57RancheroJim - 9 Years Ago This is what I use as a reference. By NoShortcuts - 9 Years Ago Paul.  Jim's info. is good.  If you don't have the FoMoCo casting numbers / letters on the rocker arm rib between the adjuster and the valve stem contact, the rocker arms are aftermarket replacement units.  There were numerous companies that made replacement units OR sold them as theirs.  Because most y-blocks between '54 and '64 used 1.43:1 ratio rocker arms, that's what most replacement rockers are, 1.43:1 ratio.  Back-in-the-day there were some companies that made 1:54:1 replacement rocker arms for replacement or performance purposes.  My memory is getting dim, but Thomas was one name and (?) Gotha (maybe not quite right) was another.  Hey, this stuff IS getting old, isn't it!      Per John Mummert's web site, - '54 - '55 have EAN letters cast on the rocker arm rib and use a jam nut  -  1.43:1 ratio - '56 have  ECG 6564 letters & numbers cast on the rocker arm rib and also use a jam nut  -  1.54:1 ratio - '57 also have ECG 6564 letters & numbers cast on the rocker arm rib, but use the self locking adjusting screw  -  1.54:1 ratio - '58 - '64 have 5751066 numbers cast on the rocker arm rib and use the self locking adjusting screw  -  1.43:1 ratio JM's got someone supplying him with new cast iron 1.54:1 ratio rocker arms.  I saw them on eBay some months ago.  I suspect that they're being produced in lot quantities.  Perhaps John's supplier made more than JM ordered and then tried marketing them, too. Hope this helps.   By 2721955meteor - 9 Years Ago 57RancheroJim (8/1/2016) This is what I use as a reference. could you measure from bearing surface to outside of adjust. i have a set that is thicker and can't id them with your drawing.thanks for any help cliff with 57ranchero By 57RancheroJim - 9 Years Ago The only rockers I had loose were 1.43 ratio