you used purchased and free in the same sentence?
there not a special "type" called race car numbers .. i do draw on paper first then scan -redraw ...you just need a HEAVY type to start ..serpintine is a common one a lot use...you probly have some right there in your computer that will look just fine ...heres a pretty common formula for quick stock car numbers ..start with a 18 in tall number ,make the STROKE 5.5"[gotta tug em a bit here and there] gap between stroke 3" ,gap between 2 numbers 2.750...border first .250 " second border .750"...drop shadow 1.5 " .thatll put you bout 22.0 tall number...then resize whole thing together to whatever you want ....examples at
www.hipsticker.com EVERYnumber on there is based off that formula and tuned from that...mkae your own! its easy and no one will have the same thing