Air Flow Research 305 Rectangle Port "Magnum" BBC 24°
AFR’s Torque Monster
These AFR 305cc rectangle port cylinder heads feature partially CNC ported intake, exhaust & chambers. Manufactured from A356 aluminum castings and premium quality valvetrain components throughout. Recommended for moderate street, or street/strip builds with displacements up to 509 cubic inches operating up to 6500 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.
These heads may have the smallest intake runner volume in AFR's lineup, but don't let their size fool you. These AFR Magnum 305cc "as-cast" heads with a CNC bowl blend will provide you with flow numbers that most medium sized heads and some larger, can only dream about. This line was designed to optimize low and mid-lift airflow, while still generating impressive peak figures. Their application should be focused on smaller cubic inch Chevy big blocks (396-502) with a primary operating range of 2,500-6,800 RPM. This range is an average and will vary with engine displacement, as well as component selection.
AFR 305cc "Magnum" big block Chevrolet heads should also be given strong consideration in larger street driven or marine applications up to 555 cubic inches, where low-rpm power and drivability are factors. These cylinder heads would be a great choice if you're looking for big torque and strong low RPM performance and still have good RPM capabilities.
The big block 305 heads come standard with AFR's trademark 3/4 inch thick head deck, reinforced rocker stud bosses and premium one-piece stainless steel 2.250" intake valves and 1.880" exhaust valves. Standard combustion chamber volume is 117cc however, these heads are available with an optional 114cc combustion chamber as well.
NOTE: 1" longer head bolts needed on four bottom exhaust bolt holes.
| Big Block Chevy 305cc Rectangle Port 24° Magnum Basic Package | |
| 100% CNC Ported Combustion Chambers | |
| Bowl Blended Exhaust Ports | |
| Bowl Blended Intake Runners | |
| Competition Multi-Angle Valve Job | |
| Stainless Steel Intake Valve - 2.250'' x 5.500'' Overall Length | |
| Stainless Steel Exhaust Valve - 1.880'' x 5.448'' Overall Length | |
| 1.625'' PAC Racing Solid Roller Dual Valve Spring, 275# Seat - .850'' max lift | |
| 10º Manley 4140 Chromemoly Spring Retainers | |
| Hardened and Machines 10º Valve Locks | |
| ARP ProSeries 7/16'' Rocker Studs | |
| AFR Adjustable 3/8'' Guide Plates | |
| Steel Shell Viton Valve Seals | |
| Hardened Valve Spring Seats | |
| Ductile Iron Intake Valve Seats | |
| Ductile Iron Exhaust Valve Seats | |
| Bronze Manganese Valve Guides |
| Big Block Chevy 305cc Rectangle Port 24° Magnum Head Specifications | |
| Head Torque w/Moly Lube | 75 Ft. Lbs. |
| Rocker Arm Stud Torque | 55 Ft. Lbs. |
| Intake Port, 1.72'' x 2.45'' w-1/2'' radius | Fel-Pro 1275 |
| Exhaust Port Gasket | AFR 6858 |
| Head Gasket Mark IV | 4.540'' Bore, Fel Pro 1017 |
| Head Gasket Mark V - VI | Up to 4.500'' Bore, Fel Pro 1047 |
| Head Gasket Mark V - VI | 4.50'' to 4.60'' Bore, Fel Pro 17049 |
| Head Bolts & Studs | Standard ARP |
| Head Bolt Washers | Manley Standard |
| Stud Girdle | AFR 033-6210 |
| Suggested Intake Manifold | Edelbrock 2907, 2927 |
| Spark Plug Starting Range | Champion C59C, Autolite 3932 |
| Combustion Chambers | 121cc Fully CNC'd |
| Intake Runner Volume | 305cc - Partially Ported |
| Exhaust Port Volume | |
| Spring Pocket can be cut to 1.750 diameter but no deeper. | |
| Valve Spacing | Standard |
| Rocker Arms | Standard |
| Valve Angle | 24°/4° Intake - 15°/4° Exhaust |
| Angle Mill, 104cc Maximum | .009'' per cc |
| Flat Mill, As Cast 108cc, CNC 114cc Maximum | .006'' per cc |
| NOTE: |
Milling may require a thicker head gasket. |
PART NUMBER: AFR-2100
Due to the ever increasing costs and limited availability of certain materials, skyrocketing shipping costs, credit card usury fees as well as the inept policies of the current administration, we can no longer provide set pricing on any products on this web site. Email directly at info@FlowTechInduction.com for the latest pricing and availability.
