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Chevy small-block LS Series v-8<br />
LS Series Cylinder Heads<br />
Part Description Material Port Valve Chamber Int Exh Int Port Ex Port Rocker Notes Page<br />
Number S size Angle CC’s Vlv Vlv Type Type Type N number<br />
12564825 Bare LS2 & LS6 Aluminum 210 15 deg 64.5 2.000 1.55 Cathedral Std LS Bolt-down Bare LS2/LS6 N/S<br />
12564824 Stock LS6 Aluminum 210 15 deg 64.5 2.000 1.55 Cathedral Std LS Bolt-down Hollow/sodium-filled valves 204<br />
12576063 Stock LS2 Aluminum 210 15 deg 64.5 2.000 1.55 Cathedral Std LS Bolt-down Solid stem valves 205<br />
88958622 CNC LS6 Aluminum 250 15 deg 61.9 2.000 1.55 Cathedral Std LS Bolt-down 11.2 <strong>com</strong>pression 205<br />
88958665 CNC LS6 Aluminum 250 15 deg 65 2.000 1.55 Cathedral Std LS Bolt-down 10.5 <strong>com</strong>pression 205<br />
88958765 CNC LS2 Aluminum 250 15 deg 64.5 2.000 1.55 Cathedral Std LS Bolt-down Solid stem valves 205<br />
12615361 Bare L92 Aluminum 260 15 deg 70 2.165 1.59 L92 Std LS Bolt-down Solid stem valves N/S<br />
12615355 Stock L92 Aluminum 260 15 deg 70 2.165 1.59 L92 Std LS Bolt-down Solid stem valves 206<br />
88958698 CNC L92 Aluminum 279 15 deg 68 2.165 1.59 L92 Std LS Bolt-down Solid stem valves 206<br />
12615879 Stock LS3 Aluminum 260 15 deg 70 2.165 1.59 L92 Std LS Bolt-down Hollow/sodium-filled valves 206<br />
12615361 Bare LS3 Aluminum 260 15 deg 70 2.165 1.59 L92 Std LS Bolt-down Bare LS3 206<br />
12578450 Bare LS7 Aluminum 270 12 deg 70 2.200 1.61 LS7 Std LS Bolt-down Bare LS7 206<br />
12578449 Stock LS7 Aluminum 270 12 deg 70 2.200 1.61 LS7 Std LS Bolt-down T<strong>it</strong>anium/sodium-filled valves 206<br />
25534428 As-cast LS7 Aluminum - 12 deg 66 2.200 1.61 LS7 Std LS Bolt-down Discontinued N/S<br />
12480005 C5R 1st design Aluminum 210 11 deg 38 2.180 1.63 C5R Std LS Shaft As-cast, no seats/guides N/S<br />
12480090 C5R 2nd design Aluminum 210 11 deg 30 2.180 1.63 C5R Std LS Shaft As-cast, no seats/guides 207<br />
19201807 LSX-L92 Small Bore Aluminum 260 15 deg 70 2.000 1.55 L92 Std LS Bolt-down Hollow/sodium-filled valves 208<br />
19201805 LSX-LS3 Aluminum 260 15 deg 70 2.160 1.59 L92 Std LS Bolt-down Hollow/sodium-filled valves 208<br />
19201806 LSX-LS7 Aluminum 270 12 deg 70 2.200 1.61 LS7 Std LS Bolt-down T<strong>it</strong>anium/sodium-filled valves 208<br />
19166981 LSX-CT Aluminum 302 11 deg 45 2.200 1.61 LSX-CT LSX-CT/DR Shaft CNC machined bare head 209<br />
19166979 LSX-DR Aluminum 313 11 deg 50 2.25-2.28 1.6-1.65 LSX-DR LSX-CT/DR Shaft CNC machined bare head 209<br />
The LS Family Production and C5R<br />
Aluminum HeadS<br />
Great cylinder-head airflow has been a key enabler of the LS Series’<br />
exceptional performance. GM Performance Parts delivers those<br />
power-building attributes to you w<strong>it</strong>h a range of production-style<br />
aluminum heads—from the LS6 heads for smaller-displacement<br />
engines to LS7 style heads for 427-inch-and-larger <strong>com</strong>binations,<br />
our aluminum heads benef<strong>it</strong> from General Motors’ extensive<br />
research and development program, ensuring maximum airflow<br />
w<strong>it</strong>hout <strong>com</strong>promises. In fact, many professional builders use our<br />
heads as straight bolt-ons, w<strong>it</strong>h no further machining. Many of our<br />
assembled heads use premium machining and materials, including<br />
CNC finishing and porting, along w<strong>it</strong>h lightweight, hollow-stem<br />
valves, sodium-filled exhaust valves and—on some heads—lightweight<br />
t<strong>it</strong>anium intake valves.<br />
Aluminum LS Family Head Technical Notes:<br />
• Manufactured from 319-T5 aluminum alloy<br />
• High-efficiency <strong>com</strong>bustion chambers<br />
• Symmetrical intake and exhaust ports<br />
• Angled spark plugs (14mm; 5 /8" hex; ¾" reach; taper-seat<br />
plugs)<br />
• 15° valve angle (except C5R and LS7)<br />
• Bolt-down-type rocker arms (except C5R)<br />
• Center-bolt valve cover hold-downs<br />
• F<strong>it</strong>s Gen III and Gen IV Small-Blocks only*<br />
A. 12564824<br />
LS6 Cylinder Head Assembly<br />
• 2.00" hollow stem intake, and 1.55" sodium-filled<br />
exhaust valves<br />
• .570" max valve lift<br />
• 210cc cathedral port intake ports<br />
• 70cc D-shaped exhaust ports<br />
• 65cc <strong>com</strong>bustion chambers<br />
• Bare head P/N 12615363 available separately<br />
A<br />
LS6 Cylinder Head Assembly (exhaust)<br />
LS6 Cylinder Head Assembly (<strong>com</strong>bustion chamber)<br />
CNC-Ported LS2 Cylinder Head Assembly (exhaust)<br />
CNC-Ported LS2 Cylinder Head Assembly (intake)<br />
A<br />
B<br />
B<br />
88958665<br />
CNC-Ported LS6 Cylinder Head Assembly<br />
(not shown)<br />
• CNC-ported aluminum performance head<br />
• 2.00" hollow stem intake, and 1.55" sodium-filled<br />
exhaust valves<br />
• .570" max valve lift<br />
• 250cc CNC’d cathedral-port intake ports<br />
• 85cc CNC’d D-shaped exhaust ports<br />
• 65cc CNC’d <strong>com</strong>bustion chambers<br />
88958622<br />
CNC-Ported LS6 Cylinder Head Assembly<br />
(not shown)<br />
• CNC-ported aluminum performance head<br />
• 2.00" hollow stem intake, and 1.55" sodium-filled<br />
exhaust valves<br />
• .570" max valve lift<br />
• 250cc CNC’d cathedral-port intake ports<br />
• 85cc CNC’d D-shaped exhaust ports<br />
• 65cc CNC’d <strong>com</strong>bustion chambers<br />
Heads P/N 12564824, P/N 88958665 and P/N 88958622 are<br />
assembled w<strong>it</strong>h the following <strong>com</strong>ponents:<br />
12565311 Intake Valves 10166344 Valve Spring Retainers<br />
12565312 Exhaust Valves 12482063 Intake Valve Stem Seals<br />
12586484 Valve Springs 12482062 Exhaust Valve Stem Seals<br />
10166345 Valve Locks<br />
12576063<br />
LS2 Cylinder Head Assembly (not shown)<br />
• Lower cost alternative to the LS6 head<br />
• 2.00" solid stem intake, and 1.55" solid stem<br />
exhaust valves<br />
• .570" max valve lift<br />
• 210cc cathedral-port intake ports<br />
• 70cc D-shaped exhaust ports<br />
• 65cc <strong>com</strong>bustion chambers<br />
• Bare head P/N 12615363 available separately<br />
• Upgrade the valves to LS6 hollow stem valves w<strong>it</strong>h<br />
P/N 17801930<br />
B. 88958765<br />
CNC-Ported LS2 Cylinder Head Assembly<br />
• CNC-ported aluminum performance head<br />
• Lower cost alternative to the CNC LS6 head<br />
• 2.00" solid stem intake, and 1.55" solid stem<br />
exhaust valves<br />
• .570" max valve lift<br />
• 250cc CNC’d cathedral-port intake ports<br />
• 85cc CNC’d D-shaped exhaust ports<br />
• 65cc CNC’d <strong>com</strong>bustion chambers<br />
• Upgrade the valves to LS6 hollow stem valves w<strong>it</strong>h<br />
P/N 17801930<br />
Heads P/N 12576063 and P/N 88958765 are assembled w<strong>it</strong>h<br />
the following <strong>com</strong>ponents:<br />
12563063 Intake Valves 10166344 Valve Spring Retainers<br />
12563064 Exhaust Valves 12482063 Intake Valve Stem Seals<br />
12586484 Valve Springs 12482062 Exhaust Valve Stem Seals<br />
10166345 Valve Locks<br />
LS2 and LS6 Head Flow Data:<br />
Lift 0.200" 0.300" 0.400" 0.500" 0.600"<br />
Stock intake 136 195 237 260 260<br />
Stock exhaust 104 135 157 169 180<br />
CNC intake 147 215 262 290 307<br />
CNC exhaust 111 155 198 210 218<br />
Chevy Ls Series<br />
* GM Performance Parts heads will not f<strong>it</strong> 4.8L and 5.3L engines<br />
due to their smaller bore sizes.<br />
A<br />
LS6 Cylinder Head Assembly (intake)<br />
CNC-Ported LS2 Cylinder Head Assembly (<strong>com</strong>bustion chamber)<br />
B<br />
* GM Performance Parts heads will not f<strong>it</strong> 4.8L and 5.3L engines<br />
due to their smaller bore sizes.<br />
Add<strong>it</strong>ional <strong>com</strong>ponents required<br />
for installation. See page 207.<br />
Available for purchase online at<br />
gmperformanceparts.<strong>com</strong><br />
204 Buy online at www.gmperformanceparts.<strong>com</strong> Buy online at www.gmperformanceparts.<strong>com</strong><br />
205
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