There are subtle changes on the outside to let onlookers know that this is no ordinary F-150, such as a custom dual-intake hood, a custom front fascia and grille combo, and Shelby badging. For the interior, Shelby adds carbon-fiber trim, billet racing pedals, custom floor mats, and a serialized plaque. For lean-burn spark-ignition engines, an oxidation catalyst is used in the same manner as in a diesel engine. Emissions from lean burn spark ignition engines are very similar to emissions from a diesel compression ignition engine. Upon failure, a catalytic converter can be recycled into scrap.
To maintain catalyst efficiency, the air–fuel ratio must stay close to stoichiometric and not remain rich or lean for too long. All of Milltek's performance exhaust systems are manufactured from T304L stainless-steel