This car is a Rattler. Built in Texas in 1966 by Mark Bratton. Two were built, this was the first. It ran in the SCCA D Sports Racing class for cars with engines under 850cc.
Engines included a McColloch outboard with a Harley-Davidson transmission, a Quincey/Mercury outboard racing engine, and a scratch-built 4-cylinder engine. The second owner installed an air-cooled Honda 750cc motorcycle engine.