12480030 - Bowtie C5R Gen III Block - 4.117"-4.160" Bore, 9.240" Deck, 2.56" Mains, 6 Bolt Main, Aluminum Block

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Pricing: $8,007.40

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This is the same block that was used in the LeMans 24 hour endurance racing C5R Corvettes and is intended for maxium effort competition engines. This block has the same production external dimensions and bosses, with the primary difference of this block to the Gen 3 production blocks is siamesed water jacket, which allows engine builders to build engines with larger bore sizes. The delivered, post hone, bore size is 4.00" and the maximum finished bore size recommended with this block is 4.160". Cylinder deck height is 9.240". This block uses a dry, pressed in liner similar to other GM Racing aluminum small blocks. Steel billet bearing caps are fitted to the block. This block features wet sump style oiling and is made from high strength A356 aluminum that utilizes a modified T7 heat treat. Production Gen 3 style cylinder heads may be used on this block, however for maximum performance, P/N 12480005 Gen 3 racing cylinder heads should be used.

  • Premium “hipped”* and X-rayed 356-T6M aluminum-alloy block casting
  • 9.240" deck height
  • Production-style oiling system
  • 6-bolt SAE 8620 dowel-located steel main bearing caps
  • 4340 premium map cap fasteners
  • For use with any LS or LSX series head
  • Unique cylinder liner material for maximum durability
  • Siamesed cylinders to support larger bores
  • 4.117" finished bore
  • 4.160" maximum bore
  • Fully blueprinted and squared
  • Production camshaft location and cam bores
  • Includes 4340 premium head studs
  • Anodized aluminum O-ring core plugs
  • No Active Fuel Management provisions
  • Supports more than 900 horsepower

Application List


Shipping Information

  • Item Requires Shipping
  • 109.7 lbs.
  • W20.6000” x H16.9000” x L26.9000”

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