Hi Rodd-
Two inch ID is what I measured on the spare W-58 I keep in the garage (long story!)
Being a cheapskate, I shop the remnant piles of hoses at West and marina stores. Maybe Defender up your way?
Lengths are from engine to muffler, then to transom.
If my memory is correct, the W-70 is almost the same engine as the W-58, but has 3″ exhaust hose and higher RPM, so I guess you could put a bigger elbow on with bigger hose, but I’m sure that 2″ ID exhaust is stock for the W-58.
Quent
Clairebuoyant #132