Another good place to advertise it is in Auto Trader (Muscle Car) and Auto round Up along with Hemmings, Racing Junk.com and similar publications and web sites. They are reasonably priced and are focused towards Gear Heads, not to mention they cover a large area.
Radio is insane and too narrow of an audience. Cable is cheap (depending where you are at) but it's too fragmented, Pittsburgh area alone has about 15-20 different Cable Markets, if you want to reach a large amount of people it would cost a fortune, even if he only did the Speed Channel.
Direct mail also works well he should make sure that every speed shop, engine builder, tranny builder and chassie builder around has flyers setting at there place of business. Flyers are cheap and these types of places usually are happy to set them out....NOT to mention it's a good way to build relationships with the owners and maybe get some sponsorship.