Breakdown of Included Items

Holley 300-631 Billet Plenum Top Features:

• Plenum top for Holley Modular Ultra Lo-Ram Intake Manifold bases 300-602 and 300-603 (sold separately)
• Designed for GM LS Gen III and IV engines equipped with GM LS1/LS2/LS6 cathedral port cylinder heads
• Bolt-through design
• With burst panel recess that can be custom machined for a standard large 6 1/8 in. x 3 1/8 in. burst panel such as 300-608 (sold separately) or equivalent
• Billet aluminum construction with a satin finish

Emissions: Not legal for sale or use on Emissions-Controlled Vehicles:

• 1966 and newer U.S. manufactured California-Certified vehicles
• 1968 and newer U.S. manufactured Federally-Certified vehicles
• 1968 and newer Foreign manufactured vehicle