Frank, your answers make it a lot easier for those of us who have these cars. For a restored, no rust, 69 Firebird 400 convertible, with newer interior, everything works, I think 20K is a starting point and it will likely go up from there.

I have an original California '69 vert, currently with a running 350-2v, with a correct vintage 400/400 sitting on stands that needs to be rebuilt and installed, plus all the other parts to make it a 400 setup (hood, hockey sticks, rally guages, etc.), and it needs paint as well.

Ive already got about 17K into mine, plus its going to need paint, engine/trans rebuilds, etc.. so that could turn out to be an additional 10-15K. So you can see how 15-20K is doable, but 20K-30k is probably more realistic for what you're after.

The big question is really... how much work do you want to do. If the answer is, not much, then plan on spending 20-30K.