03-06 6.0L CNC Fab 18mm Stage 1 Cylinder Head Set - 421020

Upgrade your 03-06 6.0L Powerstroke with these CNC Fabrication, LLC stage 1 stock replacement o-ringed cylinder heads. CNC...

Part Number: 421020

Vendor: CNC Fabrication
Availability: Many In Stock
Product Type: Cylinder Heads
Please hurry! Only 0 left in stock
Subtotal: $2,195.95
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Return Policy

Within 21 Days

California Residents:
Prop 65 Warning:
Cancer and Reproductive Harm

Upgrade your 03-06 6.0L Powerstroke with these CNC Fabrication, LLC stage 1 stock replacement o-ringed cylinder heads. CNC Fabrication Stage 1 stock replacement 18mm dowel cylinder heads for 2003-2006 6.0L Powerstroke. 


  • In-house Machined on our Sunnen seat & guide machine to exceed OEM specifications using the latest tooling
  • Brand new upgraded castings to prevent areas known in the factory heads from cracking
  • O-ringed to prevent head gasket failure
  • All new intake and exhaust valves
  • All new springs, retainers, keepers, and seals
  • Hardened valve seats to resist wear and cracking
  • Vacuum checked to ensure proper valve seat sealing
  • No core return required
  • Free ground shipping
    Brand: CNC Fabrication
    Manufacturer Part Number: 421020
    Length (in): 20.0
    Width (in): 10.0
    Height (in): 8.0
    Weight (lbs): 50.0

    Returns Policy

    You may return most new, unopened items within 21 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

    You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

    If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.


    We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

    When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

    Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

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