The Challenger couldn't compete, it's too big. That's the reason Warren Johnson was bitching when the Neon Pro Stocker came out, it was narrower than his car. It's also the reason the Dakota Pro Stock truck wasn't real competitive when they started. The Chevy S10 was way narrower. Later NHRA relented and let them narrow the Dakota but the class never really took off. And it's probably the same reason why the Mustang isn't going to be a real contender despite having a nearly identical design engine to the Hemi Mopar.
Either way they are not the stupid and totally misnamed COT one size fits all that NASCAR has. They retain their original shape although the Avenger has been converted to a 2 door. I'm sure Warren will ***** about that too until he figures a way to use it to his advantage.
Yes I know they all share many similarities in their construction but they are different.