Ball Park Estimates...
Either the three cylinder Betamarine or Universal will set you back something near or over 7K, on a pallet. That gets you the whole nine yards -- engine w/mounts, transmission, and new panel with wiring harness. The install is just patient and thoughtful labor, yours (time) or someone else ($$).
Nice winter project, IMHO. Like all projects on a boats near to a quarter century in age, it will likely involve other upgrades and maintenance... fuel systems, shaft and stuffing box, frp bed logs, etc. and some other etc.
This would also be
the best time to replace all of the original crumbling sound-deadening insulation in the engine compartment... after that old engine is out.
Cheers,
Loren
ps: remember the immortal words about yacht ownership from our very own CaptDan: The golden triangle of yacht ownership is: Time, Money, and Skill. You need two out of three!