i dont know what the engine size is but its 650 horsepower. he uses it to pull loads at county fair events and such. he doesnt get 25 mpg........he gets 25 gallons per mile!!!!
They sell 100 octane racing gas at a 76 station near where I live. It is about $8 / gal. Oof. I wouldn't be taking any long sightseeing trips if I owned BIL's truck.