There are several specifications that you will need to enter to determine a blue book value with NADA Guides.
This includes the engine, options, trailer plus location.
Select = [Boats]
Manufacturer = [Bayliner Marine Corp]
Year = 
Model = [Runabout Series / 205 BR]
Zip Code = 
Engine Note = [231-265 HP (5.0L)]
Options = [Select]
Trailer = [Select]
[Get base values]
Low Retail = $12320
Average Retail = $14080
Engine = $390