It may be best to contact your local police department to see how that is handled in your local area or state. It will also depend on where you will be storing the vehicle as I believe in most areas if it will be on the street you will need to keep it registered and legal.
I agree with the others. Call the DMV and/or the local police to ask. In the town I lived in before, you couldn't park an uninsured car in your driveway or on the road. In the apartment complex where I live in, any car that isnt up to date is towed.
I had two antique cars in my yard at one point and I was required to have a tag and insurance on at least one of them. So apparently you are allowed to have one vehicle not covered/tagged - at least that is the way it is in my area.
I would recommend checking with the DMV and insurance company in your state. Something to consider though if it has any value it may not be covered by your homeowner's insurance if something happens to it while being parked.