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Modular Head Shop 5.4L 1000+ HP Rotating Assembly - Cobra Jet Crankshaft, K1 H-Beam Rods, Diamond Competition Series Pistons, King XP Bearings

Available for 2V PI, 2V TFS, 3V and 4V applications.
Pricing: $2,249.00

Customize Your Item

- Select Block for Main Bearings -
 * required
- Select Bore Size -
 * required
- Select Dish Volume -
 * required
- Select Valve Reliefs -
 * required
- Select Wrist Pins -
 * required
- Add Ceramic Dome Coating -
 * required
- Add Lateral Gas Ports -
 * required
- Balance Rotating Assembly? -
 * required
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Modular Head Shop 5.4L 1000+ HP Rotating Assembly 

  • Cobra Jet Forged 4130 Crankshaft - 4.165" Stroke
  • Diamond 5.4L Competition Series Pistons 
    • Full Round Style Forging 
    • 1.330" Compression Distance -
      • approx .008" Piston to Deck Clearance with Stock Block 
    • .280" Down Top Ring Land 
    • Moly Coated Skirts
    • Includes 1.2mm x 1.5mm x 3.0mm Piston Ring Set 
      • Gas Nitrided Steel Top, Cast Iron 2nd, 3 Piece Oil
      • Excellent for power adder applications 
    • .180" Wall 8620 Alloy Wrist Pins with Round Wire Locks 
  • Optional Piston Upgrades
    • Lateral Gas Ports - Suggested for 20lbs + Boost 
    • .200" H-13 Tool Steel Pins - Suggested for 800 HP +
    • Ceramic Dome Coating - Thermal Barrier helps with piston fatigue  
  • K1 Technologies Connecting Rods 
    • Forged 4340 H-Beam Design 
    • 6.657" Length 
    • Supplied with 7/16" ARP 2000 Rod Bolts
    •  Approx weights:
      • Big End 454g
      • Pin End 180g
      • Total 634g
  • King XP Series Main Bearings - Select Iron or Aluminum Block 
  • King XP Series Rod Bearings 

This Diamond Piston / K1 Connecting Rod Combo for the 5.4L Engines is an excellent choice for combinations making anywhere from 600 HP to around 1200 HP. This rotating assembly can be configured for 2V PI, 2V TFS, 3V and 4V cylinder head combinations. Please see the Compression Ratio chart for a full details. 

Optional Lateral Gas Ports are suggested for boost levels over 20lbs. The gas ports allow combustion gasses behind the top ring, pushing it out harder against the cylinder walls for better sealing. 

While you will not break a .180" Wall 8620 Pin at 800 HP or even 1000 HP, we suggest the H-13 Tool Steel Wrist Pin upgrade at 800 HP for one reason...rigidity. The H-13 Pins are more rigid. We have seen plenty of wrist pin flex around the 800-900 HP mark with standard 8620 or 4130 alloy pins. The flexing wrist pin will gall up the pin bores of the piston and damage the pin bushing in the connecting rods. This simply shortens the life of both components. 

This assembly will come un-balanced unless that option is selected. There is no option for not balancing an assembly. It MUST be professionally balanced either by us or another machine shop. 
It is recommended to have us balance the assembly in house as we pay very close attention to details to get you the most accurately balanced crankshaft possible. We will also cover any heavy metal they may need to be added to the crankshaft for balancing. 

The Pistons in this kit are not always in stock. Please allow around 4 weeks for delivery. Add 7-business days for balancing option as the pistons must come here first. If you are in a rush, please check with us for availability before placing your order. 

Compression Ratios

Compression Ratios Calculated with a 3.620" x .036" Compression Thickness Head Gasket and a .008" Piston to deck clearance. 


2V TFS 38cc  2V PI 42cc  2V TFS 44cc  3V 50cc  4V 52cc 
-11.5cc Dish   12.9:1 12.1:1 11.8:1  10.9:1 10.6:1
-15.0cc Dish  12.2:1 11.5:1  11.2:1  10.4:1 10.1:1 
-20.0cc Dish 11.4:1 10.8:1 10.5:1 9.8:1 9.5:1 
-25.0cc Dish  10.6:1  10.1:1 9.9:1  9.2:1 9.0:1





Shipping Information

  • Item Requires Shipping
  • 35.0 lbs.
  • W14.0000” x H14.0000” x L28.0000”
  • Free Shipping!

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