AFR 325cc As Cast Magnum BBC Cylinder Heads
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 their 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, either one of 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 117cc’s on our 325 partially CNC ported heads, 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. 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.
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. (see footnotes here)
AFR Partially Ported BBC 325cc Flow Chart
AFR BBC 325cc with CNC Chambers Flow Chart
Basic Package Components 50% CNC Chambers CNC Bowl Blend, Intake and Exhaust Intake Gasket Match Competition 5-angle Valve Job
AFR #7626
Intake Valve, 2.300" x 5.500" Overall Valve Length
AFR #7631
Exhaust Valve, 1.880" x 5.442" Overall 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.
AFR #6850
Head Gasket, 4.540 bore, Fel-Pro #1017
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
117cc As Cast
Combustion Chambers
121cc w/ CNC Chambers
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), As Cast 108cc, CNC 114cc Maximum
Note: Flat & angle mills might require a .120 thick intake gasket. |
