Merlin III Block, Billet Splayed Caps 10.2" Deck 4.490" Bore

WOR 085110

Merlin III Bare Block

Deck Height 10.200"
Bore 4.490"

Material:  High density cast iron
Deck thickness:  .600" minimum 
Maximum recommended bore:  4.625"
Crank clearance:  4.750" stroke crank without clearancing
Deck height: 10.200"
Main caps:  Splayed steel billet main caps

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WARNING: Cancer and Reproductive Harm –


Performance Crate Engines

Prior to the availability of aftermarket blocks, performance enthusiasts were faced with the dilemma of scouring junkyards looking for 4-bolt main blocks or trying to fit 2-bolt blocks with aftermarket cap kits. Now you have a choice between standard 4-bolt main blocks with nodular iron caps and splayed billet caps. Rest assured that the 4-bolt setup will provide excellent reliability for most applications. For the serious performance enthusiast, the splayed billet setup is preferred for several key reasons. The illustration below shows a cross-section of a block casting, and the relationship between bolt holes and themeat" of the block. As you can see, the splayed bolts have a much betteranchor" due to available material thickness. The multi-directional clamping of the splayed bolts also helps improve bottom-end durability.



  • Material: High Density Cast Iron
  • Deck Height: 10.200"
  • Deck Thickness: .600" minimum
  • Cam Bearings: Standard Chevrolet
  • Main Bearings: Standard Chevrolet
  • Camshaft Location: Stock
  • Lifter Bores: Indexed (stock .8437" bore)
  • 4.240 (hone to 4.250") or 4.490 (hone to 4.500")
  • Maximum Bore: 4.625"
  • Cylinder Wall Thickness: .250" at 4.600" bore
  • Water Jackets: Expanded for better cooling
  • Lubrication: Priority main oiling system
  • Filtration: Integral mount for spin-on filter
  • Oil Pan Rails: Solid (stock width)
  • Crank Clearance: 4.750" stroke crank
  • Main Caps: Nodular iron or billet steel
  • Fuel Pump: OEM mount
  • Starter: OEM mount
  • Motor Mounts: Dual (front and side)
  • Cylinder Head Holes: Blind tapped to prevent leaks
  • Weight: Approximately 270 lbs.


Compatible with all Mark IV components

All Merlin III Blocks need finish machine work to complete.

Remember: TCM offers complete machine service and block preparation

More Information
Model WOR 085110
SKU WOR 085110
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