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Back 97 (GT40P) Uprgrade Heads (Pair)

Made in United States
97 (GT40P) Uprgrade Heads (Pair)
97 (GT40P) Uprgrade Heads (Pair) 97 (GT40P) Uprgrade Heads (Pair) < >
97 (GT40P) Uprgrade Heads (Pair)
97 (GT40P) Uprgrade Heads (Pair) 97 (GT40P) Uprgrade Heads (Pair) < >

97 (GT40P) Uprgrade Heads (Pair)

GT40P Heads F77E 1X Pair They Have Been Gone Through skimmed new freeze plugs new valve stem oil seals, valves lapped painted in black ready to go !

These are the next best thing apart from HIPO Heads in cast iron in standard Form 

F77E is the engineering prefix for the Ford GT40P cylinder head, introduced in 1997 for the Ford Explorer and Mountaineer 5.0L V8. They are highly sought-after factory iron heads that provide a noticeable horsepower boost over older stock heads, but require specific swap considerations. 

1. Identification
  • Markings: Look for a "P" or "GT40P" stamp, alongside a distinct 4-bar pattern cast into the side of the head (unlike standard GT40 heads, which feature 3 bars). 
 
2. Specifications
  • Combustion Chamber: ~59 cc.
  • Intake Port Volume: ~145-158 cc.
  • Valves: 1.84" intake and 1.46" exhaust (smaller exhaust valves than the standard GT40, which uses 1.54"). 

 

3. Key Features & Benefits
  • Power: They are a well-known dyno upgrade (adding roughly 20-30 hp) over the restrictive stock "E7" heads found on 1987-1995 Mustang 5.0s.
  • Combustion Efficiency: The spark plug is moved to a more central location within the chamber, yielding a highly efficient burn. 

 

  • 4. Swap Considerations
    If you are installing these on a classic Small Block Ford (like a 302 or 351W), you must keep these three things in mind:
    • Spark Plug Angle: The unique spark plug placement angles differently than standard heads, requiring 90-degree spark plug boots to avoid melting wires against the exhaust headers.
    • Exhaust Headers: Standard headers will bolt up, but to clear the "P" spark plug angle, you typically need "GT40P specific" headers or shorty headers.
    • Valves prings: The factory valves prings are only designed for stock camshafts. If you plan to run an aftermarket camshaft with higher lift, you must upgrade the springs to avoid coil bind and valvetrain float.
    • Heads are 25kg each 
£999.00 + VAT
£1,198.80 inc. VAT