Both the 292 and the 261 (but not the 235) use a .927" pin, same size as V8 SBC, but they can't use the same piston because of the rod length difference.
For increased stroke the new rod journal must be substantially smaller than 2.311" (the 235/261 size). The 292 is at 2.100", but the G.M.C. isn't.
The maximum stroke change (up or down) is slightly less than the difference in journal ODs: 2.311" - 2.100" = .211" or 4.1485", generally rounded down to 4.125" (3/16" increase).
