Most auto policies are Stated Value. The insurance company decides what your classic car is worth at the time of the loss. If you do not agree with them, chances are you'll need a lawyer to help you argue the point. Many classic car policies sell stated value as if it was the same as "Agreed Value". It is not! Stated Value policies pay the "Stated Value" or the "Actual Cash Value" ... whichever is less. All that stated value insurance does is help decide how much premium you pay. Only an agreed value is without hidden gotchas. If your car is stolen or totaled, you will receive the agreed value. Period.
If your car is worth more than what is listed in any value guide or has been customized, you need to have Agreed Value insurance from a reputable collector car insurance company and an accurate auto appraisal report fully documenting your vehicle.