Bigfoot VIII was the most state of the art truck to battle Equalizer. But it was banned for most of the season because of it being a bit too powerful. But in the end it won the title in 1990. Even back then Bigfoot VIII with Andy Brass, Taurus with Jack Willman, and Bear Foot with Fred Shafer were the toughest monster trucks of all time in the early 90s.
I’m not sure about the powerful part, Andy had said that people might think that the truck was high on horsepower, but the trucks design and suspension set it apart from any of the other trucks. Bigfoot 9 was out at this point and that truck with the Lenco transmission and it’s even lighter weight design made that truck ballistic.