It's possible to order custom length and diameter pushrods from Comp Cams with any tip shape and size you want. I used to do it pretty regularly when we were building roller-cammed round track engines with special ratio rocker arms and non-standard valve stem lengths. They do get a little spendy when getting them made for a 1930's designed glorified tractor engine, though!
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!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!