I've got a 97 OMC King Cobra 454/300 hp and had a problem where it wouldn't shift from neautral. The dealer looked at it and replaced the cone clutch because they said I developed a leak in the outdrive. The total cost was $1206, but it included a new shift cable to which was $200 alone. I would think you are looking at somewhere around $900 at least. Good luck finding a reputable dealer/shop and getting it done before the end of summer!