As a comparison.... I' ve engined and am restoring a 1969 Chriscraft Lancer. This boat was built with hollow fiberglass stringers, which is a feature today only in top quality boats. The boat has some collector value. The boat came with a Volvo 260 drive which was replaced with a used 280 drive ( a straight swap) The 280 Volvo drives are almost bulletproof and low maintenance, and easily handles the upgraded ( 5.7L FWC 260 HP) engine I installed..
Will I ever get my $$$ back... NO ITS A BOAT!!!! But then again I've had years of "troublefree" ( Hey , it's a boat!) boating. The only issues have been with the engine which was a new factory crate Mercruiser engine. I've redone seats, recovered deck hatches ( this era Chris has Nautolex over marine ply decks) and a pending redo of the engine box the previous owner made. Oh yeah... 10 years ago I had Ricardo rebuild the upper part of the tranny on the drive as a precaution. BTW... Bimini installed backward ( i.e. towards the bow) folding so I can flyfish easily. Some older boats IMHO are worth the trouble of a restoration, most aren't.