Afr 377cc Bbc Marine Cylinder Heads, 100% Cnc Ported, Titanium Retainers

AFR is proud to announce their new BBC Marine Cylinder Head! These AFR 377cc heads feature 100% CNC ported intake, inconel exhaust valves, hydraulic roller springs, hard coat anodizing, Titanium retainers, and high quality components throughout. These heads are best suited for large displacement (540+) Big Block Chevrolet racing engines. Component upgrades and machining options are available to customize AFR Heads to your specific build.
AFR has been manufacturing BBC Marine Cylinder Heads for over a decade with great success. Many of the top marine engine builders in the industry rely on AFR for the performance in their engines. Today we are pleased to announce that you too can receive the same great AFR performance with an easier way to order your AFR cylinder heads. These cylinder head assemblies will come complete with Inconel Exhaust Valves, Hydraulic Roller Springs, and Hard Coat Anodizing.

Note: Optional stud girdle required for 2° rolled valve angles and 1" longer head bolts needed on four bottom exhaust bolt holes. Longer pushrods might also be required.

Important: Do not port match your intake manifold to Fel-Pro gasket as it does not precisely fit AFR heads.
Basic Package ComponentsPart #100% CNC Ported Chambers, Exhaust, and IntakeCompetition 5-angle Valve Job
11/32" Intake Valve, 2.300" x5.500" O.A.LAFR #762611/32" Nail Head Exhaust Valve, 1.880" x 5.450" Overall Valve LengthAFR #7631PAC Racing Spring #1224 1.625 O.D. Hydraulic Roller, 275lbs on seat, .725 Maximum Lift, Max RPM 6500 AFR #8061
10° Titanium Retainer 1.500" O.D x 1.180" I.D x .765" I.DAFR #8507
10° 11/32" Valve Locks with lashcap recessAFR #9005ARP 7/16" Rocker Exhaust StudsAFR #6406ARP 7/16" Rocker Intake StudsAFR #6407Adjustable 3/8" Guide PlatesAFR #610911/32" Viton Valve SealsAFR #6611Hardened Spring Cup 1.740" O.D / 1.650" I.DAFR #8046Intake Valve Seats 2.450" O.D x 2.000" I.D x .375" DeepAFR #9062Exhaust Valve Seats 2.000" O.D x 1.580" I.D x .375" DeepAFR #906411/32" Intake Bronze Valve Guides .531" O.D x 2.10" O.A.LAFR #904511/32" Exhaust Bronze Valve Guides .531" O.D x 2.25" O.A.LAFR #9046
Specifications, Features, and Optional Supporting ComponentsHead Torque75 ft. lbsIntake Port GasketAFR #6854 (.120" Thick) or AFR #6856 (.060" Thick)Exhaust Port GasketAFR #6858Head Gasket, Fel-Pro #1047 (Mark V and VI)AFR #6849Head Gasket, Fel-Pro #1017-1 (Mark IV)AFR #6350Head Bolts, ARP 135-3703 (Mark IV)AFR #6306Head Bolts, ARP 135-3707 (Mark V)AFR #6308
Head Studs, ARP 235-4713AFR #6307Head Bolt Washers, ManleyAFR #6320Suggested ManifoldSuper VictorVictor Jr., Spark Plug Starting RangeAutolite 3932Combustion Chambers121cc Full CNCValve Spring Pocket Diameter1.725 O.D
Intake Port Dimension2.450"H x 1.755"W x 13/32 RadiusExhaust Port Dimension1.780"H x 2.025" WValve Angle24°/4° Intake, 15°/4° ExhaustAngle Mill
.009" per cc/Maximum 104cc Flat Mill
.006" per cc/ Maximum 114ccStud Girdle, (AFR Specific)AFR #6202Important: Do not port match your intake manifold to Fel-Pro gasket as it does not precisely fit AFR heads. Note: 1" longer head bolts needed on four bottom exhaust bolt holes.