The reason for the Cuda chassis is simple, The kit already has all the Pro Stock goodies in it and the Challenger kits do not. 
I have used the Challenger kits before and they take a bit more work as they do not have much tire clearance in the rear. And you still need a donor motor and other parts. 
 
Vintage Mopar drag cars are kind of my thing as they are all I build. 
  
Thanks for looking.