Holley's new GM Muscle Series accessories are the latest expansion to our officially licensed GM product line. These die-cast aluminum valve covers and air cleaner kits were designed to have a no-frills, modern style with prominent raised GM "Chevrolet and Bowtie" logos. Intended as an alternative to the existing GM ZZ6 accessories, Holley's GM Muscle Series dress up accessories can be the perfect addition to your engine bay if you are searching for a subtly custom variation from the OEM options. All GM Muscle Series accessories are available in four custom finishes: natural cast, polished, satin black, and factory orange (all finishes have machined "Chevrolet and Bowtie" logos aside from polished version). The Small Block Chevy center bolt valve covers (designed to fit Vortec/ZZ4/ZZ5/ZZ6) feature a generous internal height for exceptional valve train clearance and include pre-installed internal baffling, polished mounting hardware, and oil fill / PCV grommets (valve cover gaskets not included).