Re: change steering
If the boat has cable steering, you'll only have to buy a stick steering helm and cable, or make a connector to go on your motor for the cables to connect to. The steering tubes are standardized, I believe, and the steering shaft on a new teleflex style system should fit it (just contact the stick steer company and ask them---they will have a real person at teleflex to answer the phone). That's all there is to it. VERY easy to do, but not cheap. Will probably cost you about $300. You'll also have to take your shift/throttle controls off the barge and put on your boat (I'm sure you knew that already).
Good luck-I love my stick steered 65merc on my crappie boat,
JBJ