Recommended for engines with 4.000” bore or larger. Maximum competition, comp/modified drag racing, circle track, and heavy duty applications.
Dart’s new LS based PRO1 LS 15° 280cc Aluminum square port cylinder head for GM LS series small block V8 engines take performance to the next level. Offers higher performance and more versatility than factory designs.
The 15° based high performance cylinder head has better airflow, more efficient combustion chambers and more user friendly features than production LS castings. The Dart PRO1 LS 280cc cylinder head retains stock valve angles, stock valve locations and stock accessory mounting holes to make installation easy. Virtually everything else has been improved.
Heads are sold individually.
Material: RMR cast aluminum
Comb Chambers: 68cc
Intake Valve Dia: 2.165”
Intake Port volume: 280cc
Intake Port Dim: 2.600” x 1.260”
Intake Port Location: Stock LS3 location and bolt pattern
Intake Gasket: OE or Fel Pro - LS3
Exh Valve Dia.: 1.600”
Exh Port volume: 102cc
Exhaust Port Dim: 1.750” h x 1.550” w
Exh Port Location: Stock LS3 location and bolt pattern
Exhaust Gasket: OE or Fel Pro 1438
Flow, Intake: 370 cfm @ .800” lift / 28”
Flow, Exhaust: 252 cfm @ .800” lift / 28”
Manifold Accepts OE or aftermarket LS3 manifolds
Manifold Milling: .005”=1cc
Push Rod length: Always measure
Push rod Guide Plate: N/A
Retainers: Titanium
Spark Plug: Autolite AR3935
Spring Locators: 1.300” O.D.
Spring Pockets: 1.350” diameter (can go 1.550”) but no deeper on depth
Springs: 1.290” Beehive 120@1.800” 1.295” Dual 140@1.800” (1.550” option)
Valve Length: 4.880”
Valve Stem Dia: 8mm
Valve Train: OE or aftermarket LS3 valvetrain
Valve Guides: .439” O.D.
Valve Guide length: 2.100”
Valve Guide clearance: .0015” - .002” (with our .3144” dia. valve stem)
Valve Guide Spacing: 2.013”
Valve Seats: Copper Infiltrated
Valve Seat dim: Int: 2.250” x 1.950” x .375” Exh: 1.650” x 1.280” x .375”
Valve Seat angles: Intake: 32°-45°-60°-70°-80° Exhaust: 37°-45°-radius
Stud Girdle: N/A
