LS3 Cylinder Head Assembly

The LS Family Production and C5R Aluminium Heads Great cylinder-head airflow has been a key enabler of the LS-Series’ exceptional Performance. GM Performance Parts delivers those power-building attributes to you with a range of production-style aluminium heads – from the LS6 heads for smaller-displacement engines to LS7 style heads for 427-inch-and-larger combinations, our aluminium heads benefit from General Motors’ 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.

Aluminium LS Family Head Technical Notes:
• Manufactured from 319-T5 aluminium 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 C5R)
• Centre-bolt valve cover hold-downs
• Fits Gen III and Gen IV Small-Blocks only*

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

• Uses bare head P/N 12629051