A true high performance plug for an actual increase in performance. Rarely would we claim that a spark plug will increase performance, but we know if the original plug is defective, getting a proper plug will of course help. The NGK BP6HS goes a step beyond that, with an extended tip, it centers the spark in the combustion chamber and actually displaces volume, effectively increasing compression ratio. An added benefit is with the protruding electrode the plug is even more foul proof than the standard B6HS. Also, the 6 is a cooler heat range for those hard max throttle runs. A really great spark plug for your modified 67cc engine.