You could use a GEBE engine - namely the 32/40cc two stroke on the 11# gear would get you to the lower end of that figure.

Adding the Tanaka tuned pipe (available currently on ebay) will put the 32cc up to around 40-ish mph. I am not sure on the 40cc with a pipe but it might be up to 45mph with the highway gear 11#

Make sure that the brakes are up to it - the sides of cars hurt...

Jemma xx