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Chevrolet Performance 12480153

R0X Splayed-Valve Aluminum Cylinder Head, Semi-Machined

Chevrolet Performance 12480153


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Estimated to ship on 05/31/18
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Chevrolet Performance 12480153 R0X Splayed-Valve Aluminum Cylinder Head, Semi-Machined $1,150.86
R0X Splayed-Valve Aluminum Cylinder Head
  • Semi-Machined: Main surfaces, exhaust bolt pattern, valve guides, and spark plug holes

  • Chevrolet Performance 12480153 Details

    R0X 4.500" Bore Spacing

    Semi-Machined Detail:
  • Machined: Main surfaces, exhaust bolt pattern, valve guides and spark plug holes
  • Not Machined: Head bolt holes, dowel holes, intake bolt holes, pushrod holes, valve seats, valve spring seats and rocker stands

  • Great for NHRA competition with dual carburetors
  • As-cast ports and combustion chambers for professional finishing
  • Designed for mid-deck 4.500" bore center R0X cylinder block P/N 25534429
  • Special larger head-bolt pattern, 3/8" fasteners, 19 holes
  • 240cc "as-cast Peanut" intake ports
  • 78cc "as-cast Peanut" exhaust ports
  • 40cc "as-cast" combustion chambers

  • Specifications:

    Manufacturer's Part Number:

    These small block Chevy splayed-valve aluminum cylinder heads are a radical departure from standard in-line valve heads. Their splayed-valve arrangement angles both the intake and exhaust valves inward toward the center of the combustion chamber, allowing maximum valve sizing to dramatically improve airflow without increasing bore diameter. Castings have a 0.240" minimum port wall thickness so, for even greater flow, extensive modifications can be made. Sold individually, these aggressive all-out competition cylinder heads are designed to get the most power from your small block Chevy with no regard for "streetability." NHRA Competition Eliminator participants routinely produce over 1000 horsepower (naturally aspirated) with these race cylinder heads.

  • 355-T7 aluminum
  • No valve seats or guides
  • "As-Cast" Intake Ports: 240cc
  • "As-Cast" Exhaust Ports: 78cc
  • Extra-thick deck for angle or heavy flat milling
  • Valve spring pads accommodate 1.625'' springs
  • Modified Valve Angles: 16° x 4° Intake, 11° x 4° Exhaust
  • 4.400'' Bore Spacing: 45cc "As-Cast" Combustion Chambers
  • 4.500'' Bore Spacing: 40cc "As-Cast" or Unfinished Combustion Chambers
  • Spark plug location revised for angled 14mm, 5/8" hex, 3/4" reach, gasket seat plugs
  • Designed for longer-than-stock 2.200''/1.650'' valves and aftermarket shaft-mount rocker systems

  • Valve Cover Gaskets #809-10185043
  • Intake Manifold Gaskets #809-10185042
  • Custom-fabricated valve covers and intake manifold

  • Items You Need
    Some parts are not legal for use in California or other states with similar laws / regulations