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Eagle Competition Rotating Assembly, LSX w/LS3 Heads, 4.000 Stroke, 4.125-4.155 Bore, 428-434 cu.in.

Eagle Kit #'s 12936, 12944, 12938, 12946
Forged 4340 Crankshaft
Forged 4340 H-Beam Rods
4.000 Stroke
6.125 Rod Length
Balancing Options Available
24 or 58-Tooth Reluctor
Dish or Flat Top Pistons
7/16 ARP 8740 or 2000 Rod Bolts Available
Pricing: $2,889.95

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Eagle Competition Rotating Assemblies are designed to offer the ultimate strength and reliability at affordable pricing for the most demanding applications. Kits include high quality components including an Eagle Forged 4340 Steel Crankshaft; Eagle H-Beam Rods; Arias or Mahle Premium Forged Pistons; Hastings Rings; and high performance Clevite or King Bearings. Image for display purposes only.

Rotating assembly consist of the crankshaft, connecting rods, pistons and rings. Butler Performance doesn't simply install or sell rotating assemblies out of the box. Most suppliers and builders simply "box balance" based on manufacturer supplied weights.

We don't take anyone else's word when it comes to the parts we stand behind. We put all rotating assemblies through the Butler Process for quality and performance. Our internal balancing process ensures each part of the kit is put through a multi-step inspection process. We then weigh and pin fit the rods and pistons as needed. We computer balance the crankshaft to the rest of the assembly. This process ensures that all the parts of the assembly are matched to form a "Butler Performance" worthy assembly. We then document all weights and information on a balance card that ships with the assembly.


LSX w/LS3 Heads
LS3, L92, LSA Heads   Displacement
24T 58T Stroke Rod Piston 66cc 4.005 4.030 4.065 4.070 4.125 4.155
12936 12944 4.000" 6.125" 2618 Mahle -20/-25cc Inv. Dome 9.0 403 408 415 416 428 434
12938 12946 4.000" 6.125" 4032 Mahle -4cc Flat Top 11.1 403 408 415 416 428 434



  • EAG-
  • EAG-
  • Eagle
  • LSX
  • New


Shipping Information

  • Item Requires Shipping
  • 60.0 lbs.

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