F-Series F1-x


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  • Cathedral port
  • 10 and 12.8 degree inline valve angle configurations ideal for everything from naturally aspirated to supercharger, turbo, and nitrous applications.
  • Port volume:
  • Chamber volume:
  • Peak flow:
  • Standard versions designed to work with GM LS3 rockers and equivalent
  • Solid Stainless 2.135″ Intake Valve
  • Solid Stainless 1.615 Exhaust Valve
  • Interlocking valve seats (like those found in racing heads) standard
  • Accomodates up to 3/8″ straight pushrods. See rocker section for solid roller applications
  • 4.030″ minimum bore size (can be run on slightly smaller bores with proper head gasket)
  • Standard FED .660″ lift spring kit with titanium retainer (Upgrade options available)


Heads are complete and assembled. Valve covers, Oil Fill cap, and Doweled Rocker Stands included with purchase of heads.


All F-series:

  • 100% Designed, Tooled, Cast and Machined in the USA.
  • A357 T6 Aluminum Castings – T6 heat treated, low silica alloy. Similar in strength, machinability and weldability to 6061-T6 billet. Superior strength compared to all commercially available castings. 20% stronger than similar high-end castings made from A356. A357 is the same material used in most aftermarket engine blocks along with many cast aerospace components.
  • 0.750” deck structure, thicker than all stock and most aftermarket castings
  • High efficiency water jacket – by increasing efficiency the overall water jacket has been reduced for overall strength without sacrificing cooling ability for all applications including endurance racing.
  • Raised runner design on both intake and exhaust – Raised runner design allows for more efficient cylinder filling, better high-rpm operation without sacrificing low and mid-range performance. Greater flow characteristics, especially when combined with our shallow valve angles. Intake flange is extended to allow all standard manifolds to fit without modification.
  • Exhaust port exit is on center with valve – Substantially better flow characteristics. Bolt pattern moved to accommodate all standard header designs using 1-7/8” or larger headers.
  • Proprietary valve cover design – Enlarged valve cover based loosely on a SB2 pattern allows for more rocker clearance when using solid rollers, more spring clearance for larger diameter/higher lift packages. Valve covers included with purchase of heads. See valve cover section below for additional information. Valve covers are doweled and o-ringed for superior sealing and serviceability.
  •  ¼ NPT water crossover ports – better cooling capacity and more flexible installation/plumbing options.

Additional information

Weight 36 lbs
Spring kit

Hydraulic .660", Solid Roller .750"

Valve Angle

10, 12.8

Valve Cover Finish

As Cast, Powdercoated Black


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