AFR 305cc Partially CNC Ported Magnum BBC Head
AFR’s Torque Monster
The smallest BBC Rec port intake volume runners in our line-up, but don’t let
size fool you. Our partially ported 305cc with CNC bowl & chamber blend will provide you with flow numbers most medium
sized cylinder 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. The application should be focused on
smaller cubic inch Big Blocks (396-502), with a primary operating
range of 2500-6800 rpm’s (this range is an average and will
vary with engine displacement as well as component selection). These
heads should also be given strong consideration in larger street
driven or marine applications up to 555 CID, where low rpm power
and drivability are a factor. AFR 305cc cylinder heads would be a great choice if your looking for big
torque, strong low rpm performance, and still have good rpm capabilities.
The 305cc comes standard with AFR’s trademark
.750” thick head deck, reinforced rocker stud bosses, and
are equipped with premium one piece stainless steel 2.250”
intake valves and 1.880” exhaust valves. Standard combustion
chamber volume is 117cc’s on the 305cc partially ported
heads. Take note the higher flowing exhaust ports and bolt pattern are raised .375 (3/8") over stock location, this rarely affects header or chassis fitment.
Properly selecting the correct aluminum cylinder head for an application
depends on a large number of variables. Please consult with one
of our sales technicians to help assist you in making the best decision
for your particular application. (see footnotes here)
Note:
Optional stud girdle required for 2° rolled valve angles and 1”
longer head bolts needed on four bottom exhaust bolt holes.
305cc Partially Ported BBC Flow Chart
305cc Partially ported BBC with 100% CNC Chamber Flow Chart
Basic Package Components
CNC Bowl Blend Intake & Exhaust
Intake Gasket Match
50% CNC Chambers
Competition 5-angle valve job
AFR #7620
Intake Valve, 2.250" x 5.500" Overall Valve Length
AFR #7630
Exhaust Valve, 1.880" x 5.448" Overall Valve Length
AFR #8031
PAC Racing Spring #1224 1.625 O.D. Solid Roller, 275lbs on seat, .850 Maximum Lift, Max RPM 7400-7600
Specifications, Features, and Optional Supporting Components
75 ft. lbs. w/ Moly Lube
Head Torque
55 ft. lbs
Rocker Stud Torque w/ Moly Lube
AFR #6855
Intake Port Gasket, 1.720" x 2.450" with 1/2" radius or Fel-Pro #1275
Important: Do not port match your intake manifold to Fel-Pro gasket as it does not precisely fit AFR heads.
Mark V-VI-up to 4.500 Bore Fel-Pro #17048 or #1047
Head Gasket
Mark V-VI-4.500 to 4.600 Bore Fel-Pro #17049
Head Gasket
Edelbrock #2927
Suggested Manifold
Dart #6200, #6201, & #6203
Suggested Manifold
Brodix HVH #2000, #2001, #2005, & #2006
Suggested Manifold
Champion C59C Autolite 3932
Spark Plug Starting Range
Partially Ported 117cc, CNC Chamber 121cc
Combustion Chambers
Can be cut to 1.750, no deeper
Spring Pocket
Standard
Valve Spacing
Standard
Rocker Arms
24°/4° Intake, 15°/4° Exhaust
Valve Angle
.009" per cc
Angle Mill (milling options available), 104 cc Maximum
.006" per cc
Flat Mill (milling options available), Partial Port 108cc, CNC 114cc Maximum
Note: Flat & angle mills might require a .120 thick intake gasket. |
