Air Flow Research LS1 Enforcer Cylinder Head for Small-Bore 4.8L/ 5.3L As-Cast 210cc w/ 64cc Chamber

For an upgrade that’s perfect for stock and mild LS builds running below 6300 RPM, get this assembly! This LS1 Enforcer As-Cast 210cc cylinder head (1506) from Air Flow Research is a great fit. It delivers consistent port geometry and repeatable airflow without CNC porting. It’s done by using “As-Cast” tech on the runners and combustion chambers. Just like higher end CNC-ported cylinder heads, it also features PAC Racing springs and 21-4N steel valves. You can use it with 4.8L and 5.3L small-bore LS engines.

Features and Benefits:
- Fully assembled 210cc cylinder head with a 64cc chamber
- Ideal for OEM engines operating below 6300 RPM
- Made of A356 aluminum for strength, thermal stability, and reduced weight
- Features permanent mold “As-Cast” technology surfaces
- Allows extremely accurate and repeatable port location and performance
- Intake/exhaust runners and combustion chambers use “As-Cast” tech
- Intake and exhaust ports are located in stock location
- Precision 3-angle valve job enhances airflow and valve sealing efficiency
- Uses PAC Racing hydraulic roller dual spring with 1.290" O.D.
- One-piece, 8mm, 21-4N stainless steel valves for superior high-heat resistance

210cc Flow Chart (CFM @ Valve Lift):
- .200” lift: 136 CFM intake, 93 CFM exhaust
- .300” lift: 199 CFM intake, 140 CFM exhaust
- .400” lift: 246 CFM intake, 180 CFM exhaust
- .500” lift: 272 CFM intake, 204 CFM exhaust
- .550” lift: 276 CFM intake, 211 CFM exhaust
- .600” lift: 265 CFM intake, 215 CFM exhaust

Specifications:
- Minimum bore diameter 3.780"
- Combustion chamber size: 64cc
- Valve angle: 15 degrees
- Port volume: 210cc intake / 82cc exhaust
- Intake port dimensions: 3.190" height x 1.015" width x 5/16” top and 3/8" bottom
- Exhaust port dimensions: 1.400" height x 1.660" width
- Intake valve: 8mm bead lock, 2.000" head diameter, 4.900" overall length
- Exhaust valve: 8mm bead lock, 1.570" head diameter, 4.915" overall length
- Seat pressure: 140 lbs.
- Maximum RPM: 6300-6500 RPM
- Chromoly retainers: 7-degree, 1.245" O.D., .885" I.D., and .655" inner step diameter
- Valve keepers: 7-degree bead lock
- Viton valve seals: .620" O.D. and .490" I.D.
- Hardened valve spring locator: 1.380" O.D. and .570" I.D.
- Valve spring pocket diameter: 1.500" O.D.
- Maximum valve spring pocket machining: 1.500" O.D.
- Deck thickness 0.425"
- Flat milling rate: .006" removed per 1cc reduction
- Minimum combustion chamber volume after milling: 58cc  
- Spark plug dimensions (with tapered seat): 14mm x .750"

Vehicle Fitment:
- 1960-1987 Chevy C10
- 1988-1998 Chevy/GMC C/K
*MUST be equipped with a 4.8L or 5.3L small-bore LS engine

Additional Notes:
- This cylinder head is sold individually; two are required per engine.
- Do NOT machine the spring pad any deeper.