^ That's good advice.
It's pretty amazing what another $1000 can buy you in terms of saved restoration time (especially on low-dollar cars like Zs). If you are paying to have it repaired this is an extremely important ratio to understand before even getting the project car. If you are doing the work yourself and don't like wasting your time this is also a big factor.
Another thing, that even "car guys" never really seem to embrace, but constantly smacks them later, is that the rust ALWAYS worse then what you can see when you are talking about an older car.