Proflow does not sacrifice quality for a low price- you get both with our aluminium cylinder heads. Our LS3 cylinder heads are designed for street / race performance engines to give the ultimate in flow at a competitive price. Cast from A356 aluminium, these 15 LS3 rectangle port heads are designed to fit LS series engines with a 4.00" or larger bore. These bare 275cc heads accept 2.165" diameter intake valves and 1.60" exhaust valves and have a 0.625" deck thickness. Suits 6-bolt standard or LSX block designs.


  • Specifications:

  • Material: A356 Aluminium
  • Combustion Chamber: 70cc
  • Intake Port Volume: 260cc
  • Intake Port Dimension: 1.285" x 2.60"
  • Exhaust Port Volume: 100cc
  • Exhaust Port Dimension: 1.47" H x 1.64" W
  • Spark Plug Location: OE
  • Intake Valve Diameter: 2.145" x 4.89"
  • Exhaust Valve Diameter: 1.60" x 4.89"
  • Valve Stem Diameter: 8mm
  • Valve Spring Pocket I.D.: 1.30"
  • Valve Guide Material: Manganese Bronze
  • Valve Guide O.D.: 0.502" (.560" at base)
  • Rocker Design: LS3 Rails required
  • Valve Angle: 15
  • Deck Thickness: 0.625"