LT1 Single Black Label Cylinder Head - 4.125 (+) Bore - For Direct Injection or Port Injection - Bare

---->Download the Cylinder Head Spec Sheet<---- The Mast Motorsports cylinder head product line is completely manufactured from a raw casting to a finished cylinder head in the USA located in Nacogdoches Texas.  Mast refuses to compromise on materials and methods that may jeopardize longevity, performance, and quality.  When buying Mast Cylinder heads, you are getting the highest level of quality and performance on the market.  Full Send, no compromises, no shortcuts, ever. Dimensional Specs Bore Size: 4.125" (+) Weight: 30 lbs. Intake Valve Size: 2.250" Exhaust Valve Size: 1.600" Valve Stem Diameter: 5/16" Valve Length: 5.550" Intake Valve Angle: 10°x2.5° Exhaust Valve Angle: 11°x2.5° Valve Spring Pocket Diameter: 1.400" Valve Spring Install Height: 1.800" Head Stud Size: .530" Valve Guide OD: .570" Valve Job Type: Newen CNC 5 Angle Air Flow & Performance Criteria Intake Max. Flow: 391 CFM @ 0.700" Exhaust Max. Flow: 250 CFM @ 0.700" Intake Average Flow: 272 CFM Exhaust Average Flow: 180 CFM Intake Seat Material: Ductile Iron Intake Port Volume: 313cc Exhaust Port Volume: 122cc Standard Chamber Volume: 70cc Port Type: CNC Materials Cylinder Head Material: A356-T6 Aluminum Intake Valve Seat Material: Ductile Iron Exhaust Valve Seat Material: Ductile Iron Deck Thickness: .750" Rocker Stand Type: Pedestal Rocker Arm Type: LS7 Exhaust 1.8 Ratio Guide Material: Phosphor Bronze General Rocker Stand Type: Pedestal Rocker Stands Included: Built-In Rocker Stand Dowels Included: N/A Uses Stock Rocker Bolts: No Rocker Bolts Included: No Rocker Arm Type: LS7 Exhaust 1.8 Ratio Head Bolt QTY: 4 Bolt Style Valve Cover Rail Height: + ½ inch Can use OE Valve Cover: Yes Custom Options Available Chamber Softening Custom Chamber Sizing ½ inch head stud clearance Copper Exhaust & Intake Valve Seats