The Montana 500 Endurance Run was officially started in 1961 to give Model T owners a chance to get together and share their interest in Model T's. This is a timed event, perhaps unique in the world, as Montana is one of the last places to allow timed events on their public roads. The Model T's in this event must be stock, except they can have aluminum pistons, reground cams and the heads and blocks may be milled.  The first run started in Missoula and traveled all the way to the North Dakota border - over 500 miles. The run proved very popular and soon had drivers from many states and Canada, including: Florida, Illinois, Indiana, Idaho, Missouri, Washington, South Dakota, Wyoming, Iowa, Ohio, North Dakota, Kentucky, California, Colorado and Alberta. Many times, over 30 cars have participated. The 500 takes place in spectacular country, perhaps the most scenic in the lower 48 states. Huge flat green meadows surrounded by forested mountains and snow packed peaks. Nowadays to simplify logistics, the 500 is held out of a hub city. The first and second days are approximately 200-mile days and the third day is around 100 miles. Pit stops are made each 50 miles or so to gas up, get coffee, or eat lunch. The cars are flagged out at one-minute intervals and are soon jockeying for position. The cars are then flagged in at each pit stop and are timed out by order of arrival. On the second day, cars are timed out in the reverse order of the 1st day's finish. The slowest car leaves 1st and the fastest car leaves last. This gives the faster car the handicap of having to pass the slower cars. The third day the cars are timed out by their order of finish on the previous two days. Fastest cars are first and the slowest cars are last. After the 500 the first 3 cars are torn down to examine the interior of the motor for compliance with the rules. There are two classes of cars in the 500 (endurance runner and tour cars).