1970 Olds 442 Vert. What is it worth???

[KnoxvillePig]

A guy I work w/ came to me the other day and said he heard I was into musclecars, however, I do not know a whole lot about Olds 442 cars. He has a 1970 Olds 442 convertible sporting a 455 Cubic Inch motor stored away in his basement garage. It has a hurst 3 speed his/hers shifter. Power door locks with AM/FM factory Radio. The color is silver/grey. Has less than 90,000 actual miles and I think he may be the original or second owner if I can remember correctly.
Does anyone have any idea what ballpark the car is worth. I do not think he intends to sell at this time.

Thanks

Darrell