Kevin and Grant put their skills to the test when building a homemade hovercraft capable of crossing land and sea; getting a merry-go-round to produce Top Gun G-forces.

Kevin & Grant try to survive a 30mph ride through rough terrain in their Off-Road Soap Box Racers. The classic homemade Volcano gets supersized into a 3-stage eruption. Aerodynamics and a 46-year old gridiron record are challenged by a Football Cannon.