I had seen a lot of big bikes our there using a car's engine. Some just got to have a second wheel at the rear as the weight would not be possible to be supported by a human leg and transform it into being a tricycle.
Now a bigger engine can be used for that matter and why not a Semi Truck's engine? Now it gets so interesting, so if you like a sick version of a trike you could just create one using the biggest engine you can muster and turn it into a monster of a tricycle.
