Thanks, Tony & Mechainiac, for the assistance and thanks to those of you who e-mailed me offering rods. As usual, on this board I find solutions to my problems.
I'm learning more about 261 rods than most people would care to know. Spoke to a bunch of folks yesterday including Patrick's and a guy in WA, "Buffalo".???
He verified what Tony said about the ...964 casting number being a 261 rod and said that the light rod with the ...456 apparently indicated a replacement rod. Now it makes sense that the entire set of six 261 rods from the other machine shop and the 6th one I had were all light.
I have now found three sources for a 261 rod. One is only about 20 miles from Omaha. If all works as planned, will probably make a trip to pick it up today.