J.V.,
You may want to contact Mike Langlois at https://aeroracingengines.com. Mike services Nelson racing engines and may be able to rebush or remake your connecting rod. Also, try Clarence Lee and his contact can be found in the Classified Ads section of "Model Aviation" magazine. Note that Clarence can be best reached by snail mail. Finally, there was a John Ackerman that was producing conrods for the early OS DF engines, ie. OS 65 VRDF and OS 77 VRDF. I recall that he resided in the Indianapolis, IN area but have lost tract of any contact info. Good luck in your quest.
Rgds,
Art ARRO