Afr 325cc Bbc Magnum Rectangle Port Cylinder Heads

AFR's 325cc heads are designed feature partially CNC ported intake, exhaust, A356 aluminum castings and high quality components throughout. Recommended for more aggressive street, or street/strip builds with displacements up to 540 cubic inches, operating up to 6800 RPM. Also available with 100% CNC chambers for increased air flow (see chart). Component upgrades and machining options are available to customize AFR Heads to your specific build.
AFR's Best of Both Solution
Are you looking for big torque and big horsepower numbers? Our BB Chevy line of medium volume intake runners will provide you with exactly that. The phrase "having your cake and eating it to" would certainly be appropriate with the moderately sized intake runners producing tremendous flow figures across the entire lift range. These high flow/high velocity ports provide extreme versatility and fill the needs of many applications. From a max-effort high compression 454 to a 605 CID low rpm marine application, these aluminum cylinder heads would be a great choice. These heads would also be ideal in a larger cubic inch "Pro-Street" application with their broad torque range, as well as significant rpm and horsepower capability. These cylinder heads will work best with a primary operating range of 3000-7000 rpm's (This range is an average and will vary with engine displacement as well as component selection). The 325cc come standard with AFR’s trademark .750" thick head deck, reinforced rocker stud bosses, and are equipped with premium one piece stainless steel 2.300" intake valves and 1.880" exhaust valves. Standard combustion chamber volume is 115cc's on our 325 “As Cast” pieces, while the CNC Chamber 325 version comes with a 121cc chamber. Properly selecting the correct cylinder head for an application 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.

Basic Package Components Part # 20% CNC Ported Exhaust Ports
30% CNC Ported Intake Ports
50% CNC Ported Combustion Chambers
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
Manley 10° Steel Retainers 1.500" O.D x 1.168" I.D x .844" I.D AFR #8518
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 #6853 (.120" Thick) or AFR #6855 (.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 w/ CNC Chambers or 117cc w/ As Cast Chambers Valve Spring Pocket Diameter 1.725 O.D
Intake Port Dimension 2.360"H x 1.685"W x 3/8 Radius Exhaust Port Dimension 1.720"H x 1.920" W Valve Angle 24°/4° Intake, 15°/4° Exhaust Angle Mill
.009" per cc/ Maximum 104cc as cast or CNC Chamber Flat Mill
.006" per cc/ Maximum 108cc as cast or 114cc CNC Chamber Stud Girdle, (AFR Specific) AFR #6202 Important: Do not port match you intake manifold to any Fel-Pro gasket as it does not precisely match AFR heads.
Note: Milling head deck will affect flow numbers. 1" longer head bolts needed on four bottom exhaust bolt holes. Angle mills might require a .120 thick intake gasket.