Air Flow Research AFR3835 300cc Bullitt Aluminium Cylinder Heads Competition Package 75cc Combustion Chamber suit BB Ford 429-460

"Blue Oval" big block performance is alive and well at Air Flow Research with a much needed clean sheet redesign of the aging BBF cylinder head. Starting with the needlessly large OEM port our design team decreased overall runner size while giving it a more consistent cross sectional area. This change is designed to increase peak power while notably boosting the torque, responsiveness and fuel efficiency. We then carefully shaped the combustion chamber and positioned the valves to compliment intake and exhaust port design while efficiently utilizing the cylinder bore. The improvement in valve positioning allows us to address the "Achilles Heel" of the BBF head, the exhaust port. By filling the floor of the exhaust port without raising the height we have improved high flow lift while increasing flow at low and mid lifts, achieving a 75% intake to exhaust flow ratio with our exhaust port in the stock location reaching 275 cfm. The high flow stock exhaust location allows for stock header and chassis fitment, but for customers with more room AFR offers their BBF cylinder head with the exhaust port raised .250".

AFR's 285cc heads feature 100% CNC ported intake, exhaust & chambers, A356 aluminium castings and high quality components throughout with standard or .250" raised exhaust port locations. Recommended for more aggressive street/strip or racing builds with displacements up to 512 cubic inches, operating up to 6500 RPM.

Please Note: that due to AFR's valve angle and location, custom pistons or notching your existing pistons will be required.

Specifications & Features:

Material A356 Aluminum
Intake Port Volume 285cc
Intake Port Dimension 2.275" H x 1.885" W x .575° Radius
Intake Port Location Stock
Exhaust Port Volume 142cc
Exhaust Port Dimension 1.850" H x 1.600" W
Exhaust Port Location .250" Raised
Combustion Chamber Size 75cc or 85cc
Valve Cover Bolt Pattern Perimeter
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"

Components:

• 11/32" Bead Lock Intake Valve 2.250" x 5.245" O.A.L.
• 11/32" Bead Lock Tulip Exhaust Valve, 1.760" x 5.050" O.A.L.
• PAC Racing #1224 1.625" OD Solid Roller Dual Valve Spring 275 lbs. on seat, .850" maximum lift, Max RPM 7400-7600
• 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
• Hardened Valve Spring I.D Locator 1.550" O.D x .780" I.D