value of 20ft 1975 seacraft

[ScottM]

Based on the age of everything you mention, I would say no more than $5,000. From what you say, there's been no structural updates to the hull, it has a 18-19 year old engine (how many hours?), and a 23 year old trailer. With such a package, you're taking a good deal of risk making the purchase (perhaps you already know this), so anything over $5K IMO is a waste of money.