LS9 CNC-Ported Head Assembly


  • Almost 10-percent increase in airflow
  • Special A356T6 aluminum Roto-cast design for greater strength
  • Assembled with lightweight LS9 components
  • For LS engines with 4.000″ or larger bore


Out of stock

SKU: 19328743 Categories: ,

LS9 CNC-Ported Cylinder Head Assembly

P/N 19328743

  • Special A356T6 aluminum Roto-cast head casting for greater strength. The mold is rotated during production to create a more solid casting that virtually eliminates porosity
  • Reinforced webbing and thicker deck (for minimal distortion) makes it an excellent choice for supercharged and turbocharged engine combinations
  • CNC-ported for approximately 10 percent greater airflow (intake side) than the regular-production cylinder head (similar to LS3 CNC-ported head P/N 88958758)
  • As-cast 66.5cc combustion chamber volume
  • Fully assembled with production LS9 2.165″ (55mm) titanium intake valves and sodium-filled 1.590″ (40mm) exhaust valves; and beehive-type valve springs
  • Valve springs rated for .570″ max lift
  • Can be used on LS engines with at least a 4.000″ bore using standard 11mm head bolts in place of the LS9’s 12mm head bolts

Head P/N 19328743 is assembled with the following:

  • 12605524 Titanium Intake Valve (2.165″)
  • 12596508 Valve Spring Caps
  • 12605525 Sodium-FilledvExhaust Valve (1.590″)
  • 10166345 Valve Stem Keys
  • 12625033 LS9 Beehive Valve Spring
  • 12482063 Valve Seal-Intake (Integral Seal & Spring Set)
  • 12482062 Valve Seal-Exhaust (Integral Seal & Spring Set)
  • 12596509 Rocker Arm Wear Pads (Intake Valve Only)

Additional required components:

  • 12610046 (2) or 19170419 (1) Gaskets
  • 11562524 (20) Bolts
  • 12558840 (10) Bolts
  • 12571164 Spark Plugs

Engine application: LS9


LS9 CNC-Ported Cylinder Head Assembly

19328743 Chevrolet 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 ヨ from the LS6 heads for smaller-displacement engines to LS7 style heads for 427-inch-and-larger combinations, our aluminum heads benefit from GM‘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 ヨ on some heads ヨ lightweight titanium intake valves.

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

NOTE: Chevrolet Performance heads will not fit 4.8L and 5.3L engines, due to their smaller bore sizes.

Prop65WARNING: These auto parts can expose you to chemicals including phthalates and lead. Installing or using these parts can expose you to other parts containing these chemicals and to engine exhaust, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to