Thomas,
I take it that you did get a title when you purchased It ?
If not, why ?
Did they provide " YOU " a bill of sale from whom they bought it from ?
Was it a family member >> or a widow that sold you the drag car? Surely they know something, old race pictures too.
Any old paper work may also help with finding a serial number, and or where it was at before he bought it to race>
Trace back old racers or families from the old tracks around you area. Again, you need to spend lots of time, which may lead absolutely no where.
These are all but a few scenarios you need to start on.
No serial number. means you own an old cut up mustang drag car.
An expert can identify modifications "" that may or may not have been done at Shelby's place. """
respectfully submitted,
John