Replacement 5.3 Liter LT 3.780" Bore - Factory Mast OE Stock Replacement - Direct Injected - OE Valves

Factory Replacement - NO CNC Porting

Introducing Factory Mast Gen 5 LT Replacement Cylinder Heads.

Our team carefully inspects, pressure tests, machines, and qualifies our gently used factory OE heads.  We machine and qualify the deck, and all surfaces to better than factory.

Great as a factory replacement cylinder head, or for your own porting applications.

Full Send, no compromises, no shortcuts, ever.

Dimensional Specs

• Bore Size: 3.780" (+)
• Weight: 30 lbs.
• Intake Valve Size: 1.928"
• Exhaust Valve Size: 1.556"
• Valve Stem Diameter: 8mm
• Valve Length: 5.550"
• Intake Valve Angle: 12.5°x2.61°
• Exhaust Valve Angle: 12°x2.38°
  
• Valve Spring Pocket Diameter: 1.325"
• Valve Spring Install Height: 1.880"
  
• Head Stud Size: .427"
• Valve Guide OD: .500"

Air Flow & Performance Criteria

• Intake Average Flow: 217
• Exhaust Average Flow: 156
• Intake Seat Material: OE Seat Material
• Intake Port Volume: 273cc
• Exhaust Port Volume: 114cc
• Standard Chamber Volume: 58cc
• Port Type: OE Port
  

Materials

• Cylinder Head Material: 319-T7 Aluminum
• Intake Valve Seat Material: OE Seat Material
• Exhaust Valve Seat Material: OE Seat Material
• Deck Thickness: .300"
• Rocker Stand Type: Pedestal
• Rocker Arm Type: LS7 Exhaust 1.8 Ratio
• Guide Material: Powdered Metal

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

• Head Assembly