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AFR - Airflow Research 345cc Rectangle Port 24° Magnum Aluminum Cylinder Heads BB-Chevy

AFR - Airflow Research 21108035


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Estimated to ship directly from the manufacturer on 09/20/18
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AFR - Airflow Research 345cc Rectangle Port 24° Magnum Aluminum Cylinder Heads BB-Chevy $2,302.99
345cc Rectangle Port 24° Magnum Aluminum Cylinder Heads
  • BB-Chevy
  • 117cc Combustion Chambers
  • 1.625'' Valve Spring
  • 255 lbs. Seat Pressure
  • .750'' Max Lift
  • 50% CNC Combustion Chambers
  • Assembled
  • Sold in Pairs, 2/pkg.

  • AFR - Airflow Research 21108035 Details

    50% CNC Combustion Chamber (Bowl Blend) Package

    BB Chevy Basic Package Components
    Competition 5-angle Valve Job
    Intake Valve, 2.250'' stainless steel
    Exhaust Valve, 1.880'' stainless steel
    1.625'' OD Roller Dual Valve Spring with dampner, 240 lbs. on seat, .750'' maximum lift
    10º Chrome Moly Retainers
    10º Chrome Moly Valve Locks
    Valve Seals
    Hardened Shims
    Intake Valve Seats
    Exhaust Valve Seats
    Bronze Valve Guides Intake
    Bronze Valve Guides Exhaust
    Guide Plates
    7/16'' Exhaust Rocker Stud
    7/16'' Intake Rocker Stud
    BB Chevy Magnum Head Specifications
    Head Torque 75 Ft. Lbs.
    Intake Port Gasket 1.700'' x 2.430'' with 1/2'' radius
    Exhaust Port Gasket Standard
    Head Gasket 4.370 boreFel Pro 375-1027
    Head Gasket 4.540 boreFel Pro375-1017-1
    Head Gasket
    Mark V-VI-up to 4.500 Bore
    Fel Pro375-1017-1 or Fel Pro375-1047
    Head Gasket
    Mark V-VI-up to 4.500 Bore
    Fel Pro 375-17049
    Head Bolts & Studs Standard
    Head Bolt Washers Manley Standard
    Stud GirdleStandard
    Suggested ManifoldEdelbrock 350-2907 or 350-2927
    Spark Plug Starting RangeChampion C59C or Autolite 3932
    Combustion Chambers 115cc
    Spring Pocket can be cut to 1.750, no deeper.
    Valve Spacing Standard
    Rocker Arms Standard
    Valve Angle 24º/4º Intake, 15º/4º Exhaust
    Angle Mill.009'' per cc
    Flat Mill .006'' per cc


    Manufacturer's Part Number:

    AFR's 345cc Competition Ready Welterweight!

    If huge horsepower is what you are searching for, the 345 can certainly deliver. These cyilnder heads were targeted at larger cubic inch engines, 509-632ci, looking for maximum horsepower and rpm capability with a primary operating range of 3500-8000 rpm's (This range is an average and will vary with engine displacement and component selection). As well, these aluminum heads provide impressive torque figures at higher rpm levels, so higher reving 450+ cubic inches can benefit from the efficient runner. Blown, turbo, and nitrous engines will especially like the larger, higher flowing intake ports. AFR BBC 345cc cylinder heads will work best with camshafts around the .750+ gross valve lift mark to make better use of the substantial airflow found in the higher lift range. The 345cc come standard with AFR's trademark .750'' (3/4'') thick cylinder head deck, reinforced rocker stud bosses, premium one-piece stainless steel 2.300'' intake valves and 1.880'' exhaust valves. Combustion chamber volume is 117cc or 121cc and can be milled as lower if necessary. Take note the higher flowing exhaust ports and bolt pattern are raised .375'' (3/8'') over stock location, this rarely affects header or chassis fitment. .

    Installation Notes: Optional stud girdle required for 2° rolled valve angles and 1'' longer head bolt needed on four bottom exhaust bolt holes. Longer pushrods may also be required.

    345cc Rectangle Port Magnum Cylinder Head Features:
  • 50% Partially or 100% Fully CNC Ported Combustion Chambers
  • Bowl Blended Exhaust Ports
  • Bowl Blended Intake Ports
  • Competition 5-angle Valve Job
  • 345cc Intake Ports
  • Intake Valve, 2.300'' x 5.500'' Overall Valve Length
  • Exhaust Valve, 1.880'' x 5.442'' Overall Valve Length
  • 1.625'' OD PAC Racing Solid Roller Valve Spring, 275 lbs on seat, .850'' maximum lift
  • 10° Manley 4140 Chrome Moly Retainers
  • 10° Valve Locks
  • 7/16'' Rocker Studs
  • Adjustable 3/8'' Guide Plates
  • Viton Valve Seals
  • Hardened Spring Seats
  • Intake Valve Seats
  • Exhaust Valve Seats
  • Bronze Valve Guides

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