This section of the site will be devoted to some further information about this sport.
Like all sports played, has a history and owns technical information and technology concerning both components of the wheeled sled, not neglecting even any curiosity
As a mediator of the concepts that are given, you quote a phrase:

“But knowledge, as opposed to possession, can be shared for free.”
(Neil Gershenfeld, in FAB.)

History of Tractor Pulling

It is said around the 1900's when farming machines were pulled by horses farmers would boast about how strong their horses were. They would make big claims that their horse could tow large loads, such as a fully loaded hay cart or wagon. To prove this for their neighbors, farmers would challenge one another to contests to prove who had the strongest horse. So a barn door was removed and laid flat on the ground the horse was then hooked up to it and the farmer ushered the horse to drag the barn door along the ground. One by one people jumped on the door until the horse was no longer able to drag it, the horse that pulled the most people the greatest distance was the strongest.

This event called draft horse pulling is still carried out today with specially bred horses trained to have high strength and low stamina, but instead of people fixed weights on sleds are dragged as far as possible. Whilst is often said that the term horsepower is derived from this event, in reality the term was coined by James Watt when he invented the steam engine.
It wasn't until 1929 that motorized vehicles were put to use in the first events at Bowling Green, Missouri and Vaughansville, Ohio. The sport was recognized from this time but didn't really takeoff until the 50's and 60's when it was finally realised that there were no uniform set of rules. The rules from state to state, county to county were all different and competitors never knew what standards to follow which made the sport very hard to grasp for any new comers. Finally in 1969 representatives from eight different states got together to create a uniform book of rules to give the sport the structure that was needed and created the National Tractor Pullers Association.

The NTPA's early years were events that used standard farm vehicles with the motto "Pull on Sunday, plow on Monday" and it stayed basically the same way through the 70's with only stock and modified tractors. Stock tractors were the commercially available tractors made by well known manufactures and modified tractors were the basic tractor chassis with another non tractor engine mounted on it.

Tractors stayed single engine until a couple of Ohio brothers introduced the crossbox which could allow multiple engines to be attached to a single driveshaft. After this it was usual to see modified tractors with four engines while the stock tractors tried to catch up by adding intercooled turbochargers but both still retained the appearance of a tractor. Soon tractors became single use machines that were not used on the farm making the "Pull on Sunday, plow on Monday" motto a part of history.

Tractors stayed single engine until a couple of Ohio brothers introduced the crossbox which could allow multiple engines to be attached to a single driveshaft. After this it was usual to see modified tractors with four engines while the stock tractors tried to catch up by adding intercooled turbochargers but both still retained the appearance of a tractor. Soon tractors became single use machines that were not used on the farm making the "Pull on Sunday, plow on Monday" motto a part of history.

The limit of horsepower has not been reached yet: As well as piston engines jet engines made an appearance in 1974 with a four jet engined one appearing in 1989. The growing popularity of this sport created a new division in 1976 called four wheel drive which immediately caught a great fan base. The engines in these vehicles kept on growing and growing from 450 cubic inches/7.3 litres up to 700/11.5 and probably would have carried on but the NTPA capped it at 650/10.6 naturally aspirated and no blown engine in 1989. Blown engines were allowed but only in the new 1986 division of two wheel drives or "funny cars" as the NTPA called them.
Two other divisions were made: the pro-stock and the mini-modified division which was a garden lawn mower mounted with a supercharged V8.

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