Herb Adams constructed a Trans-Am race car around his wife's 64 PontiacTempest. The 80,000-mile 1964 Pontiac had a de-stroked 389-in. motor. It was entered in the opening round of the Sports Car Club of America's 1971 Trans-Am championship. Unable to qualify, the car was allowed to start from the back of the pack. It mowed through the field, and was running second behind eventual winner Mark Donahue's factory-supported Penske Racing AMC Javelin when the engine quit.
Pontiac did not want Adams to show up their Firebird, so Herb and his crew did it themselves and damn near whipped everyone. That's grassroots.