Heavy-Duty And O-Ringed: Freedom Series 6.0L Heads
With a superior casting, oversized valve seats, and O-rings as standard equipment, Fleece’s new 6.0L Power Stroke cylinder heads are poised to change the game.
In recent years, Fleece Performance Engineering has poured significant resources into what has become an industry-leading cylinder head manufacturing program. Now, the successful template the company employs for its Cummins and Duramax cylinder head lines is being applied to the 6.0L Power Stroke—an engine that’s long been known for its top-end issues. Cast, machined, and assembled in Indiana, the Freedom Series HD 6.0L cylinder heads offer improved strength and higher durability over OEM versions, while their O-ring design delivers superior combustion sealing. If you’re in need of new heads for your ’03-’07 Super Duty, this will be the last set you ever have to buy. Here’s why.
New, Improved Casting
Whether the heads on your 6.0L Power Stroke have cracked or become warped over the years, Fleece has done its due diligence to develop a product that far exceeds the OEM hardware. From the ground up, the Freedom Series HD 6.0L cylinder heads were engineered to outperform the factory versions in every meaningful way. It all starts with a brand-new casting, which boasts a higher tensile strength alloy. Then come the design enhancements, with their superior casting incorporating increased wall thickness and additional material where it’s needed most. It’s a combination that makes for a more durable, longer-lasting cylinder head in the long run.
Hardened, Oversized Valve Seats
When valve seats crack, they can end up breaking apart, falling out of the cylinder head, wrecking valves, and even damaging the piston and cylinder beneath them. While 6.0L Power Stroke heads aren’t necessarily known for dropping valve seats, they are infamous for cracking—which makes the Freedom Series HD heads the ultimate upgrade. Each one is treated to oversized, press-in valve seats, providing vastly improved stability and durability within the cylinder head. American made, race-proven, and stronger than factory, Fleece’s oversized valve seats are produced from a tungsten alloy for improved hardness, which serves to bring significantly higher wear resistance to the table.
Valvetrain Upgrades
Assembled in Freedom Racing Engines’ state-of-the-art facility, the same place that’s produced UCC-winning power plants, 3,000-plus hp dyno-melters, and earned countless wins in the dirt—each Freedom Series HD head receives all-new components, and even upgrades where necessary. In addition to the aforementioned oversized and hardened valve seats, stainless steel and Inconel alloy valves are included, along with new valve guides. On the top side of each head, you’ll find new valve springs, retainers, and keepers in place. Fully assembled (and tested) heads retail for $1,649, with no core charge for the customer, or core to return.
Single Piece O-rings
In a class all by itself, Freedom Series HD 6.0L heads are the only heads on the market that offer a single piece, hoop-style O-ring. This specific type of O-ring was chosen for its ability to guarantee complete combustion sealing, as opposed to conventional stainless wire, which has a seam. O-rings have always been highly welcomed on 6.0L Power Stroke heads, primarily due to their 4-bolt per cylinder design limiting head-to-block clamping force. O-rings come standard with every Freedom head—and heads remain fully compatible with factory Ford head gaskets (either PN KC3Z-6051-A or PN KZ3Z-6051-B).
18mm & 20mm Versions
To serve all 6.0L Power Stroke engines, Fleece offers its heads in both 18mm and 20mm dowel configurations. Versions for 18mm dowels carry part number FPE-61-10011-HD while 20mm heads carry PN FPE-61-10012-HD. It’s up to the end user to verify which version of cylinder heads their engine has, and this can be verified by locating the engine serial number on the rear, driver side of the block. It’s worth noting that all 20mm dowel heads are configured for 2-bolt rocker box configurations and that every head (18mm or 20mm) comes with a fuel return plug that must be installed prior to installation.
Recommended Supporting Parts
Fleece recommends the use of 6.4L Power Stroke pushrods (PN 8C3Z-6565-B) when installing its Freedom Series HD 6.0L heads. This is because 6.4L pushrods are 0.050-inch shorter in length in comparison to a factory 6.0L pushrod. The shorter overall length will accommodate the tolerance stack ups that are often encountered with a replacement cylinder head. And, as with any 6.0L Power Stroke application, new (and properly torqued) head studs are highly recommended—as are new inner row bolts. Follow through on the above suggestions and you’ll have a pair of heads that will likely outlive the short-block beneath them.
Written by Mike McGlothlin
