Bill, I'm not certain what year the pushrod diameter got changed. Cam grinders like Comp Cams, Isky, and others sell semi-finished pushrods that can be trimmed to the proper length for a specific application, and they offer all sorts of end shapes, ball, cup, and other custom shapes. It would be possible to duplicate a stovebolt pushrod in about any length you desire if necessary for special applications.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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