Marketplace for drag cars would be my first thought.
Car sales is a competitive, arguably saturated online market though - and I think that 'drag cars' is a bit too niche.
I think 'dragracing.com.au' would be the premium domain in this space for covering drag racing generally. Incidentally, that domain is registered but not in use.
Decent domains, but I'm not sure they would be worth developing as a marketplace, which to me seems to be the obvious use for them.
They are good terms though, and you may have some success in selling to people in the drag racing space, for example:
http://www.dragnews.com.au
http://www.andra.com.au
http://www.willowbankraceway.com.au
Of the two domains, I prefer the plural. In terms of value, I think low-mid $xxx if you can get interest from a buyer in the drag racing space.
