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Our 280cc feature partially CNC ported intake, exhaust & chambers, A356 aluminum castings and high quality components throughout with standard exhaust port locations. Recommended for street, towing, or street/strip engines with displacements up to 477 cubic inches, operating up to 6200 RPM. Please note, due to AFR's valve angle and location, custom pistons or notching existing pistons will be required.

280cc Aluminum BBF Cylinder Heads
Part # Description Combustion Chamber
3802 CNC bowl blend, Partially CNC Chamber
w/ Hydraulic Roller Springs
75cc
3803 CNC bowl blend, Partially CNC Chamber
w/ Solid Roller Springs
75cc
3805 CNC bowl blend, Partially CNC Chambers
w/ Hydraulic Roller Springs
85cc
3806 CNC bowl blend, Partially CNC Chambers
w/ Solid Roller Springs
85cc

280cc Street Head Flow Chart
  .200 .300 .400 .500 .600
Int 169 244 309 354 385
Exh 130 174 214 238 254

Test conducted at 28" of water (pressure) on Superflow 600
Bore Size: 4.380", 3/4" radius plate exhaust, 2 1/8" curved pipe

Included Components
50% CNC Ported Combustion Chambers
80% CNC Bowl Blend Intake & Exhaust
Competition 5-Angle Valve Job
11/32" Bead Lock Intake Valve 2.250" x 5.250" O.A.L
11/32" Bead Lock Tulip Exhaust Valve 1.760" x 5.050" O.A.L
PAC Racing Springs 1.550" OD Solid Roller Dual Valve Drag Race Spring 220 lbs. on seat, .680" maximum lift Max RPM 7200-7400 (upgrades available)
PAC Racing #1940 1.550" OD Hydraulic Roller Dual Valve Spring 175 lbs. on seat, .725" maximum lift Max RPM 6500-6700
10° Manley Steel Retainers 1.500" O.D x 1.120" I.D x .705" I.D
10° 11/32" Beadlock Valve Keepers with lashcap recess
ARP 7/16" Rocker Studs
Adjustable 3/8" Guide Plates
11/32" Viton Valve Seals
AFR #6610
Hardened Valve Spring I.D Locator 1.550" O.D x .780" I.D
Intake Valve Seats 2.450" O.D x 1.950" I.D x .375" Deep
Hardened Valve Spring I.D Locator 1.550" O.D x .780" I.D
11/32" Bronze Valve Guides .502" O.D x 2.250" O.A.L
Specifications & Features:
Material
A356 Aluminum
Intake Port Volume
280cc
Intake Port Dimension
2.230" H x 1.815" W x .525 Radius
Intake Port Location
Stock
Exhaust Port Volume
132cc
Exhaust Port Dimension
1.830"H x 1.600"W
Exhaust Port Location
Stock
Combustion Chamber Size
75cc or 85cc
Valve Cover Bolt Pattern
Perimeter Bolt
Valve Angle
14° Intake/8° Exhaust
Valve Spring Pocket Diameter
1.750" O.D
Max Valve Spring Pocket Machining
1.750" O.D
Deck Thickness
.750"
Minimum Bore Diameter
4.360"
Minimum Cross Sectional Area
3.225 sq. in.
Spark Plug Dimensions
14mm x .750" w/Gasket Seat

Footnotes

  1. AFR Big Block Ford

    • Heads are designed for 3/8" pushrods. Larger pushrods will not fit without clearancing and is not recommended since some areas are very thin. AFR recommends the use of .120" thick-wall pushrods.
  2. General Recommendations for AFR Cylinder Heads:

    • Bar Codes - Please keep the bar code & paperwork shipped with your head, these contain all the specs for your heads when calling AFR.
    • Pushrods - Different length pushrods might be required, always check pushrod length. Check pushrod clearance with heads placed on the block before final assembly. Larger pushrods will not fit without clearancing and is not recommended since some areas are very thin. AFR recommends the use of .120" thick-wall pushrods.
    • Mills - Flat or angle mills could affect flow numbers and might require a thicker intake gasket.
    • Stud Girdles - Due to many available factory OEM and aftermarket style/variations your existing stud girdle may not fit (AFR heads require AFR Stud Girdles)
    • Boosted/Nitrous Applications - We strongly recommend considering Inconel exhaust valves and AFR's optional heavy duty intake valve for power adder applications. Since boosted or nitrous oxide applications accelerate RPM quickly, additional spring pressure is required. We strongly recommend upgrading your valve springs or increasing your valve spring pressures since boost pressure on the valve reduces spring tension. For example, 15lbs boost on a 2.125 OD valve reduces the springs closed seat pressure by approximately 40-45lbs.
    • All MARINE Applications - We strongly recommend Inconel exhaust valves & also offer a hard anodized coating to slow the effects of corrosion. Please see note on guide clearance below.
    • Valve Guide Clearance - Your AFR Heads come with proper guide clearance (.0012"-.0016") for most applications. Boosted/Nitrous or marine applications might require additional clearance and it is the customer's responsibility to verify proper clearance in these applications.
    • Valve Springs - Forced induction, nitrous oxide and cams with aggressive ramp rates may require additional spring pressure. We offer optional valve springs for these types of applications. AFR also recommends the use of billet cam cores and short travel Hydraulic Roller lifters which tolerate higher spring loads. Please don't hesitate to contact us directly if you question which spring is correct for your application.
    • AFR Titanium Valves - Might require lash caps and different length pushrods. Titanium valves are coated, do not grind valves because it removes the protective coating.
    • Piston to Valve - AFR assumes no responsibility for damage if the end user builds an engine without properly verifying he has enough piston to valve clearance (depth and radial clearance both checked). We recommend a minimum depth of .080" on the intake valve and .100" on the exhaust with a radial clearance of .020" minimum around the perimeter of each valve. Clay is recommended to visually verify both depth as well as radial clearance. Just checking depth is not enough, the position of the valve pocket must also be addressed. It is the customers responsibility to verify proper piston to valve clearance.
    • CNC Porting - Occasionally a 100% CNC ported head might have a very small area left "as cast", this in no way affects performance.
    • Shaft Mount Rockers - Shaft mount rockers might require additional clearance for proper pushrod fitment. Do not clearance the push rod area as the wall is .060" thick.
    • Spring Installation - To ease installation with 1.550" O.D or larger springs, 12 pt head bolt or studs are recommended for extra clearance. Beveled or ground washers might be needed (ARP #200-8504 comes with smaller O.D and doesn't need to be ground)
    • Rocker Arms - Use full roller rocker arms, roller tip rockers with stock style bodies are NOT recommended.