AFR 345cc As Cast Magnum BBC Cylinder Heads
AFR’s Magnum Series
If “Dirty Harry” drove a racecar, it would certainly be
fitted with a pair of our 357cc “Magnum” cylinder
heads. If huge horsepower is what you are searching for, either
of these castings will certainly deliver. With our fully CNC ported
357cc flowing 425 CFM it can produce upwards of 900 HP. These cyilnder 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). As well, these aluminum heads provide impressive torque figures
at higher rpm levels, so higher reving 450+ CIDs can benefit from the efficient runner. Blown, turbo, and nitrous engines will especially
like the larger, higher flowing intake ports. AFR BBC 357cc cylinder 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 357cc come standard with AFR’s
trademark .750” thick cylinder head deck, reinforced rocker stud bosses, PAC 1.625 racing springs rated to .850 lift,
and are equipped with premium one piece stainless steel 2.300”
intake valves and 1.880” exhaust valves. Standard combustion
chamber volume is 121cc for our 357cc BBC and can be milled as low as 102 cc's if necessary. 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
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)
345cc BBC Partially CNC Ported Flow Chart
345cc BBC with CNC Chambers Flow Chart
Basic Package Components CNC Bowl Blend Intake & Exhaust Intake Gasket Match 50% CNC Chambers 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 #6856
Intake Port Gasket, 1.720" x 2.450" with 1/2" radius, 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), 104cc 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. |
