Bill,
I never will figure out airplane prices. Friend of mine put his very nice Bellanca 7ACA Champ (the new Champ series, built in the early '70s) with an 0-235 engine conversion on the market at $39,900 and it sold within 48 hours.
Yet, for that money, there are some decent 310s I could buy (but never afford to operate).
The price for the 150 is more than twice what I'd expect to pay for one of that vintage, time and modest avionics. I saw nothing about IFR certification or an IFR GPS.
But, as you say, it just takes one buyer.
I am, however, familiar with the concept of owners thinking their airplanes are worth a heck of a lot more than reality and how incensed they get at even a mention of Vref and Blue Book prices.... (And, how surprisingly accurate Vref tends to be...)
Best regards,
Rick
