The last time I had a vehicle that did not have any paper work. I had to get what was known as a bond title. I had to try to notify the last registered owner first. When that failed, I got a bond from an insurance company for the worth of the vehicle (incase it turned up stolen they would pay for it) anyway after the bond period the vehicle was titled to me. I cannot remember the amount of time required. This was the way it was handled in California years back.
