Not sure I understand the question. You have an electric hub on it now. You want to put an electric hub on it and a gasoline engine kit. Or you just want to install a gasoline kit.

If it is the latter you just need to buy the special mounting kit on ebay then use the regular kit. I think.

for the other two I have no idea.

__________________
visit my blog for Riding in the hood,... The home brew bike journal....http://frictiondrivebicycles.blogspot.com/ The deacon's fiction