Hey JayBoy18,
Drag Cars regardless of their type cannot be sold between civilians. The only way your can sell you vehicle is through Thompsons Auto Salvage and Sales.
I'm not 100% sure of the reasoning behind the this, however, I do know that at you dealerships (Sunshine/PDM) these vehicles are always sold at cost price.
In short, you cannot sell your drag vehicle to another civilian direct
Regards, Freestyle