The growing popularity of the sport caused the creation of a new four-wheel drive division in 1976, which captured a large fan base. The engine sizes in these vehicles continued to increase, from up to and probably would have continued, but the NTPA limited it to naturally aspirated and no blown engine in 1989. Today the 4-wheel drive division is one of the most popular with the success of trucks like the Holman Brothers "4-Play" Chevy and Bob Boden's "Studley Studebaker".