[bmxmon]

Your are pretty much always going to be able to get a nicer mustang down south (or another rust free area) than up north/the rust belt. A 65 coupe up here in minnesota, lets say for $5000, might have some rust in the normal places, where as down south for $5k you could probably get a rust free car. There is really no exact number, as there are too many variables in old cars. Why are you asking this by the way?