NGK TR6 Spark Plug 4177 for Shelby GT500/4.6L/5.4L

NGK TR6 Spark Plugs. Set of 8. Ideal for 5.4L and 5.8L GT500 Engines, Boosted 4.6L and 5.4L Engines. 1 Heat range colder than stock. Recommended gap .028-.032 or consult with your tuner. 

14mm plug thread. Uses a 5/8 Spark plug socket for install and removal.