Which ST .35 series? The bushing .35C series, or G.21 series? I ran the snot out of two .35C's with zero failures.
FWIW, it was fairly common to replace OS .35S rods with ST .35 rods (OS rods weren't bushed and wore quickly). Some aftermarket rods have been made in small batches for the OS .35S, so it seems like they should also retrofit into a ST .35....or at least, some ST .35's. I'd ask Randy Smith, and Leonard Neuman (Stuka Stunt Works). Brian Gardner in Australia might also be able to help.

Steve