In the SCCA there are some very serious SR competitors. They spend a lot of money on their cars. It's not uncommon for the fastest cars to have one off custom built engines. Don't confuse that with a "racing" version of a production engine, these are clean sheet, ground up, custom engines. Many use heads and cylinders from a production design engine, often a single cylinder engine, and attach them to a custom built crankcase/crankshaft in a multi cylinder configuration. It sounds like this car might have such an engine. Very cool stuff but you've got to have piles of money (and lots of knowledge) to design and build one. Kohler used to sponsor such a car/team that won many runoffs races.