Update 11 April, 2018
The engine was bolted into the Ground Test Vehicle using elastomeric (cushioned) engine mounts almost identical to the ones scheduled for the flying prototype. The Samson engine is being located further to the rear than the original Hayabusa engine was. This will help provide correct center of gravity without having to weld heavy steel weights to the rear of the GTV, as was required earlier. Additionally, this will allow a passenger to be carried in the GTV to record video and other data, and to gain a passenger viewpoint on ride quality.
Above you can see the engine at home behind the seats of the GTV, with the rear right wheel in the foreground. The GTV is just a welded tube representation of the Switchblade flying sports car chassis, and is no true representation of the final carbon fiber vehicle. It is very handy for testing and proving such things as steering, ride quality, and in this case, performance of the engine and transmission.