AFR 23° SBC Cylinder Head 227cc Competition Package Heads, Standard Exhaust, 75cc Chambers

AFR's 227cc "Race Ready" and "Competition" heads are engineered to deliver peak performance, featuring 100% CNC ported intake, exhaust, and combustion chambers. These heads are constructed from A356 aluminum castings and are equipped with high-quality components throughout. Designed with 60/40 valve spacing, they require shaft mount rocker arms for optimal valve train geometry, and can also be used with .050 offset intake rockers for drag race applications only.

Included Components

100% CNC Ported Combustion Chambers
100% CNC Ported Exhaust Ports
100% CNC Ported Intake Ports
Competition 5-angle Valve Job
8mm Bead Lock Intake Valve, 2.100" x 5.000" Overall Valve Length
8mm Bead Lock Exhaust Valve, 1.600" x 5.030" Overall Valve Length
PAC Racing Spring 1.550" OD Solid Roller Dual Valve Spring, 220 lbs on seat, .710" maximum lift, - 260* max recommended duration, Max RPM 7200-7400
10° Steel Retainers 1.500" O.D x 1.120" I.D x .705" I.D
10° Bead Lock Valve Keepers with lashcap recess
ARP 7/16" Rocker Studs
Adjustable 5/16" Guide Plates
Viton Valve Seals .600" O.D x .495" I.D
Hardened Valve Spring I.D Locator 1.550” O.D x .780” I.D
Ductile Iron Intake Valve Seats 2.200" O.D x 1.750" I.D x.375" Deep
Ductile Iron Exhaust Valve Seats 1.696" O.D x 1.325" I.D x .305" Deep
8mm Bronze Valve Guides .502" O.D x 2.100" O.A.L

227cc Race Ready™ & Competition Flow Chart

227cc Race Ready™ Flow Chart:

.200	148	116
.300	210	155
.400	261	204
.500	296	220
.550	304	225
.600	312	229
.650	315	233
.700	318	237

227cc Competition Flow Chart:

.200	152	120
.300	212	160
.400	260	214
.500	292	230
.550	310	234
.600	316	238
.650	322	241
.700	327	243
.750	329	245

*Test conducted at 28" of water (pressure) on Superflow 1020.*

Specifications & Features

Material: A356 Aluminum
Intake Port Volume: 227cc
Intake Port Dimension: 2.200" H x 1.290" W 5/16 Radius
Intake Port Location: Stock
Exhaust Port Volume: 80cc
Exhaust Port Dimension: 1.430" H x 1.540" W
Exhaust Port Location: .250" Raised
Combustion Chamber Size: 65cc or 75cc
Valve Cover Bolt Pattern: Perimeter Bolt
Valve Angle: 23°
Valve Spring Pocket Diameter: 1.580" O.D
Deck Thickness: .750"
Minimum Bore Diameter: 4.000"
Flat Mill: .006" per cc 60cc Maximum
Angle Mill: .009" per cc 55cc Maximum
Spark Plug Dimensions: 14mm x .750" w/Gasket Seat
CARB Status: THESE PRODUCTS ARE ILLEGAL TO OPERATE ON ANY PUBLIC HIGHWAY. THESE PRODUCTS ARE ONLY LEGAL IF USED ON A DEDICATED RACING VEHICLE. VIOLATION ARE SUBJECT TO A MAXIMUM PENALTY OF $37,500 PER VIOLATION PER VEHICLE, REVOCATION OF REGISTRATION BY DMV, LOSS OF USE ON PUBLIC RIGHT OF WAYS AND PROOF OF CORRECTION OF THE TAMPERING.