I bought an '86 1660 for $17,500 w_ 2400 hrs 3 months ago. It is in very good shape w rock trap, reverser, fore aft, std rotor. I found a dealer that had to move it. Communs motor, spec rotor all add value. 20-25k would be market. If it is early '90s it could push 30k. keep in mind most 1660 are getting up there in yrs.