Frank's suggestion is a good one. Go to the 'Home' page of John Mummert's web site at
http://www.ford-y-block.com/Scroll down to the section titled 'Rocker Arm Parts for Y-Block Ford Engines' and toggle the picture of the rocker arm assemblies.
The web page that opens refers to the availability of complete rocker arm assemblies.
However, IF you call John, I believe that he will sell you the number of individual rocker arms that you need.
His phone number in El Cajon, California is 619-596-0312
Hope this helps.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York