LS3 Medium Bore | Factory Mast | As Cast Port | Cylinder Head - Pair w/ Valves

Expected Ship Date February 2025

---->Download the Cylinder Head Spec Sheet<----

----> Download the Dyno Report Here <----

Introducing the Factory Mast "As Cast" Port Cylinder Head.                                           

We launched our Factory Mast product line to deliver an economical product line for our customers. 

We completely engineered and manufactured our long standing best in class CNC port into an "As Cast" port.  This new process saves a significant amount of time and manufacturing cost, which is savings we pass down to you.

You have come to love the "Black Label" Cylinder heads, but now you can get the same quality at a lower price without SACRIFICING performance.

Manufactured using permanent mold technology, this casting is simply an amazing surface finish and quality.  

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: 4.000 (+)
• Weight: 28.5 lbs.
• Intake Valve Size: 2.165"
• Exhaust Valve Size: 1.600"
• Valve Stem Diameter: 5/16"
• Valve Length: 5.450"
• Valve Angle: 11°
• Valve Spring Pocket Diameter: 1.580"
• Valve Spring Install Height: 1.800"
• Head Stud Size: .4375"
• Valve Guide OD: .502"
• Valve Job Type: As Cast

Air Flow & Performance Criteria

• Intake Max. Flow: 358 CFM @ 7.000"
  
• Exhaust Max. Flow: 230 CFM @ 7.000:
• Intake Average Flow: 236 CFM
• Exhaust Average Flow: 160 CFM
• Intake Seat Material: High Chrome Alloy Steel
• Intake Port Volume: 255cc
• Exhaust Port Volume: 106cc
• Standard Chamber Volume: 70cc
• Port Type: As Cast
  

Materials

• Cylinder Head Material: A356-T6 Aluminum
• Intake Valve Seat Material: High Chrome Alloy Steel
• Exhaust Valve Seat Material: High Chrome Alloy Steel
• Deck Thickness: .750"
• Rocker Stand Type: Mast Billet
• Rocker Arm Type: OE LS3 1.7 or Aftermarket
• Guide Material: Bronze

General

• Rocker Stand Type: Mast Billet
• Rocker Stands Included: Yes
• Rocker Stand Dowels Included: Yes
• Uses Stock Rocker Bolts: No
• Rocker Bolts Included: No
• Rocker Arm Type: OE LS3 1.7 or Aftermarket
• Head Bolt QTY: 6 Bolt Style
• Valve Cover Rail Height: + ½ inch
• Can use OE Valve Cover: Yes

Custom Options Available

• Head Assembly
• Custom Chamber Size
• Chamber Softening
• 1/2" Head Studs