Racing Flag

PARTS INTENDED FOR COMPETITION USE ONLY.
Click for more details.

Racing Flag

PARTS INTENDED FOR COMPETITION USE ONLY.
Click for more details.

SMALL-BLOCK SPLAYED-VALVE ALUMINUM RACE CYLINDER HEADS

12480146

ROUGH-MACHINED SPLAYED-VALVE ALUMINUM CYLINDER HEAD 

  • Main surfaces are machined, exhaust bolt pattern is machined
  • Head bolt and dowel holes, intake bolt holes, spark plug holes, and pushrod holes are not machined
  • Valve guides, valve seats, valve spring seats, and rocker stands are not machined
  • Valve locations and angles may be relocated
  • 240-cc “as-cast” intake ports
  • 78-cc “as-cast” exhaust ports
  • 45-cc “as-cast” combustion chambers

12480147

SEMI-MACHINED SPLAYED-VALVE ALUMINUM CYLINDER HEAD

  • Main surfaces are machined; exhaust bolt pattern, valve guides, and spark plug holes are machined
  • Head bolt holes, dowel holes, intake bolt holes, and pushrod holes are not machined
  • Valve seats, spring seats, and rocker stands are not machined
  • 240-cc “as-cast” intake ports
  • 78-cc “as-cast” exhaust ports
  • 45-cc “as-cast” combustion chambers
  • Same casting as P/N 12480146

24502517

SPLAYED-VALVE ALUMINUM CYLINDER HEAD 

  • Semi-machined aluminum race head
  • 240-cc “as-cast” intake ports
  • 78-cc “as-cast” exhaust ports
  • 45-cc “as-cast” combustion chambers
  • Same casting as P/N 12480146

12480153

SPLAYED-VALVE 4.500 BORE CENTER ALUMINUM CYLINDER HEAD

  • Semi-machined aluminum race head
  • Great for drag racing competition with dual carburetors
  • As-cast ports and combustion chambers for professional finishing
  • Use mid-deck block with 4.500" main bore machining
  • Special larger head-bolt pattern, 3/8" fasteners, 19 holes
  • 240-cc “as-cast” peanut intake ports
  • 78-cc “as-cast” peanut exhaust ports
  • 40-cc “as-cast” combustion chambers

88958684

SPLAYED-VALVE 4.500 BORE CENTER ALUMINUM CYLINDER HEAD CUBED

  • Great for drag racing competition with dual carburetors
  • 240-cc “as-cast” peanut intake ports
  • 78-cc “as-cast” peanut exhaust ports
  • Cubed aluminum race head
  • Bare head, no seats or guides

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Unless specifically noted to the contrary herein, vehicles equipped with Chevrolet Performance parts that are emissions-related may not meet U.S., Canadian, and state and provincial laws and regulations relating to motor-vehicle emissions. These parts are designed and intended for use in vehicles operated exclusively for competition: in racing or organized competition on courses separate from public streets or highways. Visit www.chevroletperformance.com/emissions for more details.

  • CHEVROLET PERFORMANCE PARTS COMPLIANCE WITH EMISSIONS STANDARDS

    Motor vehicle emissions standards are intended to help achieve and maintain air quality goals that benefit human health and the environment. U.S. federal and state and Canadian law prohibits knowingly removing, modifying, or making inoperative, or causing someone to remove or render inoperative, or otherwise tampering with, any part or element of design installed in compliance with motor vehicle emission standards on a motor vehicle or nonroad vehicle, or otherwise modifying any required emission and noise control system. Unless specifically noted to the contrary herein, vehicles equipped with Chevrolet Performance Parts may not meet emissions laws and regulations and should not be operated on public roads or used for any other use. This part is intended primarily for use in vehicles that are NOT:

    (1) “motor vehicles” designed for street use; or

    (2) off-road vehicles used for anything but competition.

    U.S. federal and state, and Canadian provincial agencies have the authority to administer substantial monetary penalties against individuals and companies who do not comply with these laws. Chevrolet Performance customers are responsible for ensuring their use of Chevrolet Performance Parts complies with applicable federal, state/provincial and local laws, regulations and ordinances, and for ensuring that modified vehicles are operated in a manner that complies with applicable laws. In an effort to help consumers maintain compliance with emissions regulations, the product descriptions for many parts include emissions-related warnings and notices. This page summarizes the emissions-related information that you may see on this website.

    PARTS INTENDED FOR COMPETITION USE ONLY

    Chevrolet Performance offers parts that are intended exclusively for use in competition vehicles that will only be driven on a track or off-road course. By “competition vehicles,” GM means vehicles (i) used exclusively for competitions organized and sanctioned by a local or private body and (ii) not designed for use on public streets or highways. Consumers are strongly advised not to install parts accompanied by this warning on vehicles that will be driven on public roads, as they are not designed for that purpose. The product descriptions for such parts are accompanied by the “Checkered Flag” warning icon.

    WARNING: NOT EMISSIONS LEGAL FOR STREET USE

    Because of their effect on a vehicle’s emissions performance, certain parts are intended exclusively for use in competition vehicles. The “Checkered Flag” warning icon means a part is designed and intended for use in vehicles operated exclusively for competition: in racing or organized competition on courses separate from public streets or highways. Installation or use of this part on a vehicle operated on public streets or highways is likely to violate U.S., Canadian, and state and provincial laws and regulations relating to motor vehicle emissions.

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