Unless you've got some real financial need, I'd say keep it. You'll never be able to replace it in-kind for that amount. If you're intent on selling then I'd say $40k at a min., especially if you've got photos/receipts of the rebuild.
Since there are so few left, I think what it started out as is almost irrelevant to its value, unless it's a numbers matching RT or HEMI. As long as it's clean and well done. Yours obviously appears to be both.