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

AFR's 377cc heads feature 100% CNC ported intake, exhaust & chambers, A356 aluminum castings, 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.
Fully CNC Ported Magnum BBC Cylinder Heads! AFR 377's are ideal for large cubic inch combinations (540-615 CID) that are looking for more airflow but want to retain a 2.300 intake valve. This head will also work well on smaller very aggressive applications (489-532 CID) turning over 8000 RPM's. The 377 is very efficient and moves a lot of air early in the curve (415 @ .600) making it an ideal choice if your limited to how much cam lift you can run, such as a big inch marine engine with a hydraulic roller cam and a limited RPM ceiling. With close to 440 CFM of peak flow it should be extremely easy to clear 950 HP in a single four barrel aggressive applications and even more in well sorted out combinations (especially with tunnel ram/sheet metal dual quad combo's). The exhaust ports are also notably stronger making the 377 an excellent choice in a forced induction or nitrous car that could benefit from the stronger exhaust flow. Of course the 377cc comes standard with AFR’s trademark .750" thick cylinder head deck, reinforced rocker stud bosses, PAC 1.625 racing springs rated to .850 lift, and are equipped with premium one piece stainless steel 2.300" intake valves and 1.880" exhaust valves. Standard combustion chamber volume is 121cc for our 377cc BBC. Properly selecting the correct cylinder head depends on a large number of variables. Please consult with one of our sales technicians to assist you in making the best decision for your particular application.

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 Components Part # 100% CNC Ported Chambers, Exhaust, and Intake Competition 5-angle Valve Job
11/32" Intake Valve, 2.300" x5.500" O.A.L AFR #7626 11/32" Nail Head Exhaust Valve, 1.880" x 5.450" Overall Valve Length AFR #7631 PAC Racing Spring #1224 1.625 O.D. Solid Roller, 275lbs on seat, .850 Maximum Lift, Max RPM 7400-7600 AFR #8031
10° Titanium Retainer 1.500" O.D x 1.180" I.D x .765" I.D AFR #8507
10° 11/32" Valve Locks with lashcap recess AFR #9005 ARP 7/16" Rocker Exhaust Studs AFR #6406 ARP 7/16" Rocker Intake Studs AFR #6407 Adjustable 3/8" Guide Plates AFR #6109 11/32" Viton Valve Seals AFR #6611 Hardened Spring Cup 1.740" O.D / 1.650" I.D AFR #8046 Intake Valve Seats 2.450" O.D x 2.000" I.D x .375" Deep AFR #9062 Exhaust Valve Seats 2.000" O.D x 1.580" I.D x .375" Deep AFR #9064 11/32" Intake Bronze Valve Guides .531" O.D x 2.10" O.A.L AFR #9045 11/32" Exhaust Bronze Valve Guides .531" O.D x 2.25" O.A.L AFR #9046
Specifications, Features, and Optional Supporting Components Head Torque 75 ft. lbs Intake Port Gasket AFR #6854 (.120" Thick) or AFR #6856 (.060" Thick) Exhaust Port Gasket AFR #6858 Head Gasket, Fel-Pro #1047 (Mark V and VI) AFR #6849 Head Gasket, Fel-Pro #1017-1 (Mark IV) AFR #6350 Head Bolts, ARP 135-3703 (Mark IV) AFR #6306 Head Bolts, ARP 135-3707 (Mark V) AFR #6308
Head Studs, ARP 235-4713 AFR #6307 Head Bolt Washers, Manley AFR #6320 Suggested Manifold Super Victor Victor Jr.,  Spark Plug Starting Range Autolite 3932 Combustion Chambers 121cc Full CNC Valve Spring Pocket Diameter 1.725 O.D
Intake Port Dimension 2.450"H x 1.755"W x 13/32 Radius Exhaust Port Dimension 1.780"H x 2.025" W Valve Angle 24°/4° Intake, 15°/4° Exhaust Angle Mill
.009" per cc/Maximum 104cc Flat Mill
.006" per cc/ Maximum 114cc Stud Girdle, (AFR Specific) AFR #6202 Important: 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.