Afr 345cc Bbc Magnum Rectangle Port Cylinder Heads, Cnc Chambers

AFR's 345cc heads are designed feature partially CNC ported intake, exhaust & chambers, A356 aluminum castings and high quality components throughout. Recommended for more radical street/strip, "Pro Street", or racing builds with displacements up to 572 cubic inches, operating up to 7000 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 "As Cast" Magnum Series
If "Dirty Harry" drove a racecar, it would certainly be fitted with a pair of our 345 or 357 "Magnum" cylinder heads. If huge horsepower is what you are searching for, either of these castings will certainly deliver. With our Race Ready "As Cast" 345cc flirting with 400 CFM and our fully CNC ported 357cc flowing 425 CFM, these heads represent the ultimate in airflow for your BB Chevrolet. These heads were targeted at larger cubic inch engines (509-632 CID) looking for maximum horsepower and rpm capability with a primary operating range of 3500-8000 rpm's (This range is an average and will vary with engine displacement and component selection). These heads will also provide impressive torque figures at higher rpm levels. Blown, turbo, and nitrous engines will especially like the larger, higher flowing intake ports. These heads will work best with camshafts exceeding .750 gross valve lift to make better use of the substantial airflow found in the higher lift range. The 345cc heads 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 the 345 "As Cast" model. 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 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.

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 # 50% CNC Ported Combustion Chambers
20% CNC Ported Exhaust Ports
30% CNC Ported Intake Ports
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 #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 w/ CNC Chambers & 117cc w/ As Cast Valve Spring Pocket Diameter 1.725 O.D
Intake Port Dimension 2.435"H x 1.765"W x 13/32 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: 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. Note: Angle mills might require a .120" thick intake gasket.