I'm not too sure about dirt tracks, but I think I know what you're refering to. You're best bet is to find a local track and see what classes they run. The track should also be able to provide you with rules/regs. & $costs$ involved. VWF Racing & the Garris bros. race @
www.mahoningspeedway.com which is a paved asphalt 1/4mi oval. MVS list all rules on thier site.