I'm not saying it's right, but if you have been involved in dirt track stock car racing you already know the body is just barely there anyway....just a skin really,and they never stay straight...usually replace every year or close to it. I have never raced dirt track but my family does,and has, for many years...so I have been around it. The amount of work put into building one of those cars is insane..so if the car is in good shape besides the body you still did ok for 1 grand. And for 600 bucks you can't get much in the way of an engine and trans.
Did you tell the seller you were not happy?