[Woodz428]

The L is a little toss, it was used for the early 221 V8, as well as the Cammer( not too many of those), it was most used with the later 250 I6 that wasn't introduced until 1969. The rest of the code with the exception of the L is a 1966 Mustang convertible. Since it isn't a Mustang, the L could have been anything and altered at the time of registration to hide a stolen or totaled title. In about 1980, the Feds ( I believe) started requiring 17 digit serial numbers....which a state issued # would have to follow... as you can tell that one falls way short of that.
With that serial # and without seeing any pics, I feel pretty strongly that it is a kit titled with an 1966 Mustang convertible serial number with an altered engine code. The titling will be illegal and the altered serial number might add another level of illegality to the #. Oh,have I said be afraid..be very afraid??
I'm not sure how the other companies did titling, but I got a couple lost titles from TU in the 70s, by sending them the number off the car and transfering it to them, they would issue a new title for the car. They checked to see if it was stolen or owned by someone already, but never required even a photo of the tag. If the owner went to them or anyone that titled like that, they could have taken that number from any Mustang convertible they saw and changed the engine code so it wouldn't appear anywhere when they checked. I imagine it was that lack of follow up on TUs part to verify that it was a REAL serial # on a Real car that got them the legal issues that gave them such a black eye. He may have even owned the Mustang the number was off, depending on the level of integrity he has. From what he seems to be portraying...I'd say his integrity is questionable.
I'd suggest searching TU( or Titles Unlimited) on this forum and you might get a huge education about Cobra titling.