many years ago a guy named John Baker raced these trucks and sold a hop up set of parts using the Mikuni muscle cam, Doug Thorley Tri - y header, and your choice of 3 different carb setups - 32/36 and 38 Webers and dual 44MM sidedraft Mikunis (weber dcoe workalike). With the 38 dges, cam and header was good for about 140 hp to the wheels, dual 44s was 160 hp. With a ported head, add about 20 hp. To help with the large tires, a gear change to 4.22 or 4.63s are in order. If you are real lucky, you might find a set of ultra rare 4.97s that Baker sold back in the day. Your mileage will vary...