Car Design Software

Is there any good car design software out there? I am planning a full 4 door 67 Impala and 67 Mustang Coupe build. But I would prefer to sit down and kind of "go over and draw out" my plans first. I know you need 3d model software...but is there a specific one good for classics? I'll be doing it mainly stock, but there will be lots of customization to them. Any help would be great! :) Thanks!