I run the 350 class.
Actually ,modified partial streamliner/fuel -350cc four stroke. In September I will be back in the 250 class with my new engine.
My top speed was set with a 265cc engine.
The thing is ,the most powerful engine I ever built was a 250cc. The 265 only had more midrange.
This is a link to the home page.
http://ecta-lsr.com