These 'Racer' version LS series engine valve covers are designed with the high performance street & outright race engine in mind. The main advantage of the tall series LS rocker cover is its ability to fit over most types of aftermarket rocker-gear without the use of a spacer. Other benefits include factory style baffled breathers and enough material at the front and the back of the covers to add -08AN fittings for race style breather systems.