Chevrolet/ Holden Commodore Performance LS3Aluminium Cylinder Head

Great cylinder-head airflow has been a key enabler of the LS-Series’ exceptional performance. Chevrolet Performance delivers those power-building attributes to you with a range of production-style aluminum heads – from the LS6 heads for smaller-displacement engines to LS7 style heads for 427-inch-and-larger combinations, our aluminum heads benefit from Chevrolet Performance’s extensive research and development program, ensuring maximum airflow without compromises. In fact, many professional builders use our heads as straight bolt-ons, with no further machining. Many of our assembled heads use premium machining and materials, including CNC finishing and porting, along with lightweight, hollow-stem valves, sodium-filled exhaust valves and – on some heads – lightweight titanium intake valves.

LS3 Cylinder Head Assembly
• Aluminum performance head
• Fits any LS family engine with 4.000" bore or larger
• 2.165" hollow stem intake, and 1.590" solid stem exhaust valves
• .550" max valve lift
• As-cast L92 style intake ports
• D-shaped exhaust ports
• As-cast combustion chambers

Head P/N12629063 assembled with the following:
• 12569427 Intake Valves
• 10166344 Valve Spring Retainers
• 12582719 Exhaust Valves
• 12482063 Intake Valve Stem Seals
• 12625033 Valve Springs
• 12482062 Exhaust Valve Stem Seals
• 10166345 Valve Locks

Aluminum LS Family Head Technical Notes:
• Manufactured from 319-T5 aluminum alloy
• High-efficiency combustion chambers
• Symmetrical intake and exhaust ports
• Angled spark plugs (14mm; 5/8" hex; 3/4" reach; taper-seat plugs)
• 15° valve angle (except C5R and LS7)
• Bolt-down-type rocker arms (except LSX-DR, LSX-CT)
• Center-bolt valve cover hold-downs
• Fits Gen III and Gen IV Small-Blocks only