everything.... and I mean everything adds to or lowers the price. New brakes, old brakes - Interior good, or tears - paint- chrome - engine smokes? All make a difference to what i'd pay on a 58. Solid body for sure makes it worth buying, but not necessarily adds a lot to the price you want to pay. Each thing you have to do to make if safe and reliable above what you're buying reflects in the price you want to pay. $6000? Not unless it's had a lot of mechanical work and the body is nice. I'd agree in the $2500 range but so hard to tell without pics.