I also have done a bit of research on the OEM cam fitted to the 250 CID Mercruiser Marine 165 engine. Here is what the cam spec's. are if I were to purchase a new cam today.
Duration .192/.192
Lift .403/.403 @ .050
Total Duration . 288/.288 @ .004
I have not evaluated any RV or otherwise performance cams to get a comparison.
Al