A good way to test the market would be to like a previous post and put out a paper. Cycle News is gone so there is a void. Put a grass roots effort into stories, tests, history, mods, and maintainance. All the aftermarket companies would jump at a chance for an introductory ad rate to get the thing funded. It needs to be complete for that "first impression". Get it to market using vendors that follow Nationals, SX, GNCC, local track, etc. Set out to break even at best as an incentive to get all involved. Monitor market response and see if it will become a real business.
Posting a prototype mockup un this site with a comments section would be a good way to start.