THE LS FAMILY ALUMINUM HEADS The LS Family of GM engines has continued our tradition of raising the power potential of the legendary small-block V-8. The LS6 cylinder head came as standard equipment on the amazing 405-horse Z06 Corvette and the 2005 Corvette with the LS2 engine. These heads can be installed on any 1997-2005 LS Family of V-8 engines (except 4.8L & 5.3L versions), and the GM
Performance Parts engineers have even designed fully-CNC-ported versions to get your late model GM engine screaming right along. Our complete assemblies come with bee-hive valve springs and light weight hollow stem valves—innovations that our competitors have had to copy to catch up to our designs. We’ve already done the validation of these heads in competition in our show room stock C5R Corvette racecar, so you can be assured our LS6 race heads will live up to your demands.
Aluminum LS Family Head Technical Notes:
• Aluminum 356-T6
• High efficiency combustion chambers
• Symmetrical intake and exhaust ports (not mirrored like Gen I small block)
• Angled spark plugs, (14mm, 5/8" hex, 3/4" reach, taper-seat plugs)
• 15 valve angles (except C5R and LS7)
• Bolt-down type rocker arms
• Center-bolt pattern valve covers required
• Will not work on Gen I or Gen II small-block  A. 12564824
LS6 Cylinder Head Assembly
• Fits any 1997-2007 LS Family engine*
• 2.00" hollow stem intake, and 1.55”sodium filled exhaust valves
• .570" max valve lift
• 210cc “Cathedral port” intake ports
• 70cc D-shaped exhaust ports
• 65cc combustion chambers
• Bare head P/N 12564825 available separately 
88958665
CNC-Ported LS6 Cylinder Head Assembly (not shown)
• CNC-ported aluminum performance head
• Fits any 1997-2007 LS family engine*
• 2.00" Hollow stem intake, and 1.55" sodium filled exhaust valves
• .570" max valve lift
• 250cc CNC’d “Cathedral port” intake ports
• 85cc CNC’d D-shaped exhaust ports
• 65cc CNC’d combustion chambers
• Bare head P/N 12564825 available separately 88958622
CNC-Ported LS6 Racing Cylinder Head Assembly (not shown)
• CNC-ported aluminum racing head
• 2.00" Hollow stem intake, and 1.55" sodium filled exhaust valves
• .570" max valve lift
• 250cc CNC’d “Cathedral port” intake ports
• 85cc CNC’d D-shaped exhaust ports
• 62cc CNC’d combustion chambers
• Bare head P/N 12564825 available separately Heads 12564824, 88958665 and 88958622 are assembled with the following components:
12565311 Intake Valves 10166344 Valve Spring Retainers
12565312 Exhaust Valves 12482063 Intake Valve Stem Seals
12586484 Valve Springs 12482062 Exhaust Valve Stem Seals
10166345 Valve Locks 12576063
LS2 Cylinder Head Assembly (not shown)
• Lower cost alternative to the LS6 CNC head
• Fits any 1997–2007 LS family engine*
• 2.00" Solid stem intake, and 1.55" solid stem exhaust valves
• .570" max valve lift
• 210cc “Cathedral port” intake ports
• 70cc D-shaped exhaust ports
• 65cc combustion chambers
• Bare head P/N 12564825 available separately  B. 88958765
CNC-Ported LS2 Cylinder Head Assembly
• CNC-ported aluminum performance head
• Lower cost alternative to the CNC LS6 head
• Fits any 1997–2007 LS family engine*
• 2.00" Solid stem intake, and 1.55" solid stem exhaust valves
• .570" max valve lift
• 250cc CNC’d “Cathedral port” intake ports
• 85cc CNC’d D-shaped exhaust ports
• 65cc CNC’d combustion chambers
• Bare head P/N 12564825 available separately 
Heads 12576063 and 88958765 are assembled with the following components:
12563063 Intake Valves 10166344 Valve Spring Retainers
12563064 Exhaust Valves 12482063 Intake Valve Stem Seals
12586484 Valve Springs 12482062 Exhaust Valve Stem Seals
10166345 Valve Locks
LS2 & LS6 Head Flow Data:
Lift 0.2 0.3 0.4 0.5 0.6
Stock intake
136 195 237 260 260
Stock exhaust 104 135 157 169 180
CNC intake
147 215 262 290 307
CNC exhaust 111 155 198 210 218  C. 12582713 NEW
L76/L92 Cylinder Head Assembly
• Aluminum performance head
• Higher flow than cathedral port LS heads
• Fits any LS family engine with 4.00" bore or larger
• 2.16" solid stem intake, and 1.59" solid stem exhaust valves
• .510" max valve lift with stock springs
• As-cast “rectangle port” intake ports (not compatible with LS7 intakes)
• D-shaped exhaust ports
• As-cast combustion chambers
• Uses bare head P/N 12582714 
Head 12582713 is assembled with the following components:
12590771 Intake Valves
10166344 Valve Spring Retainers
12582719 Exhaust Valves 12482063 Intake Valve Stem Seals
12589774 Valve Springs 12482062 Exhaust Valve Stem Seals
10166345 Valve Locks
L76/L92 Head Flow Data:
Lift 0.2 0.3 0.4 0.5 0.6
Intake 154 225 275 309 330
Exhaust 121 154 180 194 202 The LS Family Aluminum Heads Continued
 A. 12480090
Bare C5R Racing Cylinder Head
• 355-T7 “as-cast” Aluminum racing head
• Professional porting and machining of combustion chambers required
• No seats or guides
• C5R Rectangle port design—requires rectangle port intake manifolds
• Designed for 2.180"/1.625" valves
• Valve angle revised to 11
• Machined for 1.625" diameter valve springs & .500" guides
• Designed for big bore LS7/C5R/LSX block
• 210cc “as-cast” intake ports
• 70cc “as-cast” exhaust ports, same as production LS6
• 30cc “as-cast” combustion chambers
• All fasteners are metric
• Valve cover rails have O-ring groove for .125" O-ring
• Capable of over 800 horsepower! 
12578449
LS7 Cylinder Head Assembly (not shown)
• 356-T6 aluminum head
• Fully CNC’d ports and chambers
• C5R/LS7 rectangle port design—requires rectangle port intake manifold P/N 25534394 or 12568976
• Assembled with 2.20” titanium intake and 1.61” sodium filled exhaust valves
• 12 valve angle
• Designed for big bore LS7/C5R/LSX block (min 4.065" bore)
• 270cc CNC’d intake ports
• 85cc CNC’d exhaust ports
• 70cc CNC’d combustion chambers
• All fasteners are metric
• Capable of over 600 horsepower
• Bare head P/N 12575450 available separately This head is assembled with the following components:
12591644 Intake Valves 12596508
Valve Spring Retainers
12578455 Exhaust Valves 12482063 Intake Valve Stem Seals
12578457 Valve Springs 12482062 Exhaust Valve Stem Seals
10166345 Valve Locks 12596509 Intake Valve Lash Cap
LS7 Head Flow Data:
Lift 0.1 0.2 0.3 0.4 0.5 0.55 0.6 0.7
Intake 71.0 145.0 222.0 271.0 315.0 332.0 348.0 352.0
Exhaust 60.0 120.0 159.0 192.0 207.0 214.0 219.0 221.0 25534428 NEW
LS7 Bare Unported Cylinder Head (not shown)
• 356-T6 aluminum head
• C5R/LS7 rectangle port design—requires rectangle port intake manifold P/N 25534394 or 12568976
• Machined for 2.20"/1.61" valves
• Designed for big bore LS7/C5R/LSX block (min 4.065" bore)
• Limited availability 17801930
LS6 Hollow Stem Valve Kit (not shown)
• Kit of (4) intake and (4) exhaust valves originally for LS6 engines to drop right into your LS2 head
• One kit services one head LS Series Cylinder Heads Part Description Material Port Port Valve Chamber Int Exh Plug Heat Rocker Notes Page Number Size Type Angle CC's Vlv Vlv Type Riser Stud Number
12480005 C5R 1st design Aluminum 210 Rec C5R 11 deg 38 2.18 1.63 Angled No Shaft As-cast, no seats/guides N/S
12480090 C5R 2nd design Aluminum 210 Rec C5R 11 deg 30 2.18 1.63 Angled No Shaft As-cast, no seats/guides 230
12564824 Stock LS6 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Hollow/sodium filled valves 228
88958622 CNC LS6 Aluminum 250 Cath 15 deg 61.9 2.00 1.55 Angled No Bolt 11.2 compression 228
88958665 CNC LS6 Aluminum 250 Cath 15 deg 65 2.00 1.55 Angled No Bolt 10.5 compression 228
12564825 Bare LS2 & LS6 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Bare LS2/LS6 228
12576063 Stock LS2 Aluminum 210 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Solid stem valves 229
88958765 CNC LS2 Aluminum 250 Cath 15 deg 64.5 2.00 1.55 Angled No Bolt Solid stem valves 229
12582714 Bare L92 Aluminum 260 Rec L92 15 deg 70 2.16 1.59 Angled No Bolt Bare L92 229
12582713 L92 Aluminum 260 Rec L92 15 deg 70 2.16 1.59 Angled No Bolt Solid stem valves 229
12578450 Bare LS7 Aluminum 270 Rec LS7 12 deg 70 2.20 1.61 Angled No Bolt Bare LS7 230
12578449 Stock LS7 Aluminum 270 Rec LS7 12 deg 70 2.20 1.61 Angled No Bolt Titanium/sodium filled valves 230
25534428 As-cast LS7 Aluminum — Rec LS7 12 deg 66 2.20 1.61 Angled No Bolt As-cast, bare head 230
19153789 NEW
Bare Block Completion Kit, Gen III (not shown)
• Includes all parts to complete a Gen III bare block
The kit includes:
PART NUMBER QTY DESCRIPTION
12575742 01 Valley Cover
12561211 01 Cam Sensor
11515756 08 Bolt
12570471 01 Valley Cover
12561243 01 Front Cover
11515758 08 Bolt
12572014 01 Rear Crankshaft Seal Housing
12556127 12 Bolt
12602972 01 Rear Crankshaft Oil Seal
12574293 01 Rear Crankshaft Seal Housing Gasket
12573460 01 Oil Galley Plug
11588949 02 Oil Plug
09427693 04 Water Drain Plug
01453658 02 Transmission Alignment Dowel
12561663 01 Water Drain Plug
12556437 01 Camshaft Retainer Plate | 
