The eight scale club I belong to's rulebook lists the following:
1. The standard race course shall be oval in shape, have two parallel straightaways, and be a minimum of sixty feet from the closest shore
2. Course dimensions must be turns 60 to 120 feet in diameter and straightaways 275 to 400 feet in length
3. The starting line shall be located near the middle of the straightaway nearest to the pit area
As you can see, race courses can have quite a variance in sizes. My particular club is an APBA sanctioned group. I don't know what NAMBA has for requirements. This is also for a scale hydro club. I don't know what class Ron was listing. He'll have to tell you that.