[Commodore]

82,
Were the car mine and if it is truly an original Shelby GT 500 I would rebuild what you have. People are obsessed with "numbers matching". If you ever decide to sell it with an other than original engine, the after market engine (no matter how prestigious the manufacture) will not add any value and perhaps detract from its interest. Your "blown motor" needs some defining details before you make or ask for help in making such a decision. How extensive is the damage? Upon your description, the replies will come.
RB