Some people have put the HKS 60 hp, four cycle engine on the GT 400 and cruise at 90 mph. Although Quicksilver says Vne is 73 mph, they say they have tested it over 90 mph with no problem.
What is interesting about this one is the fact that it has a yoke and four position flaps. You don’t see many small aircraft like that. Even if you strip it down, you can’t get it down to the Ultralight weight, so it has to be N numbered.