Other than a "58 car" am I missing what the car is? You can't compare the car to other A cpes or any other model, or some other purchase made, with limited information and expect a responsible input. Coupe has been assumed. If so, does it have all matching numbers, original colors, complete, intact, no rust some rust, no wrecks some damage? Is it a super or normal? Have any interesting options like a sunroof?
All those things affect value a great deal these days. Just a dry coupe, one owner with no special options.....if condition is as you describe, if you can buy it under $40,000 that is real value for the money. If it is as described, a $25000 car would probably sell in 10 minutes once it hit the internet. Matts input is very good.....and succinct.
Roy Smalley
www.eurowerks.com