I have an 85 with the original carbed 351w. It still runs great. Depending how often you want to do a little wrenching the better question would be standard distributor vs. electronic ignition imho. If you're able to do tune ups and similar items yourself, no problem. If you're taking it in for any work that needs to be done, E.I. and fuel injection are both worth a fair bit. Hard to believe there haven't been responses to this earlier. Just started going through the posts.
BTW, first posts should always include pics of the boat.
I spent most of my money on booze, broads and boats. The rest I wasted. - Elmore Leonard