Pro Stock Motorcycle, formerly known as Pro Stock Bike is a drag racing class that is the two-wheeled equivalent of Pro Stock. It has been a feature of NHRA drag racing since the 1980s when it was added to the professional class structure and has since spread around the globe. Their 1st Points Championship Season took place in the 1987 NHRA Season. The class has for years been dominated by inline-4 cylinder Suzuki based bikes but in recent years Harley-Davidson based V-twin machines have become more competitive due to favorable rule changes. Frames are purpose-built specifically for drag racing and are not based on their road-going counterparts.