Slidin' in a cam. 165 HP inline 6 cyl.

[Dodgerrr]

Okay, just a reminder that I had to replace the engine in the boat and I took it out of our old combine. Now, after some research I have found that most 250 in line 6's had a different camshaft than the Mercruiser. The difference is originally the boat had 165 HP and this engine has 140-145 HP. All on account of the camshaft. Being a diesel mechanic, most of the older engines I have worked on never even had cam bearings, primarily Perkins diesels.
My Question is ... Can I just slide in the new (proper) cam and lifters with out changing the bearings? Has anyone done this? The engine still has very good oil pressure. The extra 20-25 HP would explain why it takes so long to get up on plane. Both engines have flat top pistons so I don't believe that higher valve lift will be an issue.