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AFR Big Block Chevy 305cc Rectangle Port Magnum Aluminum Cylinder Heads


AFR - Airflow Research
AFR Big Block Chevy 305cc Rectangle Port Magnum Aluminum Cylinder Heads

AFR's 305cc Intake Port Torque Monster!

The smallest big block Chevy rectangle port intake volume runners in AFR's line-up, but don't let size fool you. This partially ported 305cc cylinder head features a CNC bowl & chamber blend that will provide you with flow numbers most medium sized cylinder heads (and some larger) can only dream about. This line was designed to optimize low and mid-lift airflow, while still generating impressive peak figures. The application should be focused on smaller cubic inch Big Blocks (396-502ci), with a primary operating range of 2500-6800 rpm's (this range is an average and will vary with engine displacement as well as component selection). These heads should also be given strong consideration in larger street driven or marine applications up to 555ci, where low rpm power and drivability are a factor. AFR 305cc cylinder heads would be a great choice if your looking for big torque, strong low rpm performance, and still have good rpm capabilities. The 305cc comes standard with AFR's trademark .750'' thick head deck, reinforced rocker stud bosses, and are equipped with premium one-piece stainless steel 2.250'' intake valves and 1.880'' exhaust valves. Standard combustion chamber volume is 117cc's on the 305cc partially ported heads. 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. Made in USA.

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.

305cc 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
  • 305cc Intake Ports
  • Intake Valve, 2.250'' x 5.500'' Overall Valve Length
  • Exhaust Valve, 1.880'' x 5.448'' 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


  • 4 Products
    100% CNC Combustion Chamber Package

    033-2100-1
    305cc Rectangle Port 24° Magnum Aluminum Cylinder Heads
  • BB-Chevy
  • 121cc Combustion Chambers
  • 100% CNC Combustion Chambers
  • Assembled
  • Sold in Pairs, 2/pkg.
  • $2,535.58
    Order Today Ships 09/10/15
      033-3050-1
    305cc Rectangle Port 24° Magnum Aluminum Cylinder Heads
  • BB-Chevy
  • 121cc Combustion Chambers
  • 100% CNC Combustion Chambers
  • Bare Head Only
  • Sold in Pairs, 2/pkg.
  • $2,123.33
    Order Today Ships 09/10/15
    50% CNC Combustion Chamber (Bowl Blend) Package

    033-2100
    305cc Rectangle Port 24° Magnum Aluminum Cylinder Heads
  • BB-Chevy
  • 117cc Combustion Chambers
  • 50% CNC Combustion Chambers
  • Assembled
  • Sold in Pairs, 2/pkg.
  • $2,328.00
    Order Today Ships 09/10/15
      033-3050
    305cc Rectangle Port 24° Magnum Aluminum Cylinder Heads
  • BB-Chevy
  • 117cc Combustion Chambers
  • 50% CNC Combustion Chambers
  • Bare Head Only
  • Sold in Pairs, 2/pkg.
  • $1,851.73
    Order Today Ships 09/10/15

    4 Products