Dart PRO1 Small Block Chevrolet Platinum 200cc/64cc 23° Aluminium Bare Cylinder Head
Street performance, restricted oval track, and marine performance upgrade. Mid-range to 6,500 RPM. Best for 383-434 cubic inch engines.
Dart PRO1 23° 200cc Platinum series heads offer increased air flow at high valve lift for large displacement engines. Long wearing Bronze valve guides, screw-in studs, multi-angle intake seats with hardened, radiused exhaust seats are standard. Best of all, our precision cast ports produce outstanding airflow without time consuming porting.
Heads are sold individually
Part# 11320010P
Material: RMR Cast Aluminum Alloy
Comb Chambers: 64cc
Intake Valve Dia: 2.02”
Intake Port volume: 200cc
Intake Port Dim: 2.000” x 1.190”
Int Port Location: Stock
Intake Gasket: Fel-Pro # 1205
Exh Valve Dia.: 1.600”
Exh Port volume: 75cc
Exhaust Port Dim: 1.375” x 1.325” w
Exh Port Location: Stock location & bolt pattern
Exhaust Gasket: Fel-Pro# 1404 or 1405
Flow, Intake: 264cfm @ .500” lift / 28”
Flow, Exhaust: 180cfm @ .600” lift / 28”
Head Bolts: Dart bolt kit PN# 66220011
Head Studs: Dart stud kit PN# 66120011
Manifold: Alum Single Plane Dart PN# 42411000
Milling: Min. 58cc = .060” (.0065” = 1cc) Flat Mill
Angle mill .125” safely / .200” = 49cc 1.5° (carefully)
Pistons: Most 23°aftermarket pistons.
Push Rod length: Stock thru +.100” Should always measure (Stock length = 7.800”)
Push rod Guide Plate: Dart adjustable guide Plate PN# 27001410
Retainers: Steel (10°) / 1.250” (7°)
Spark Plug: straight, .750” reach, gasketed seat
Spring Pockets: 1.550” OD (.030” deeper max)
Springs: Our Assembly: 1.250S = 120# @ 1.700” / .510” max
1.437D = 130# @ 1.800” / .600” max
1.550D = 215# @ 1.900” / .690” max
Valve Length: Std. = 4.915” w/ 1.250 & 1.437 / 5.015” (+.100) w/ 1.550
Valve Stem Dia: .3415” - 11/32”
Valve Train: STD SBC 3/8” or 7/16” stud mount
Valve Guides: .439” OD Int = Mag-bronze Exh = Mag-bronze (.002” press) .530 seal
Valve Guide length: 2.100”
Valve Guide clearance: .0014” - .002” (with our .3415 dia. valve stem)
Valve Guide Spacing: 1.890” moved .030” from stock
Valve Seats: Powdered Metal, .006” press
Valve Seat dim. Int - 2.160”x 1.810” x .350” Exh - 1.650”x 1.350”x .350”
Valve Seat angles: Int = 32° - 45° - 60° - 70°- 80° Exh = 37° - 45° - radius
Stud Girdle: Dart stud girdle PN# 64110002
Torque: Head Bolts = 70 ft/lb
Rocker Studs = 55 ft/lb
Manifold = 35 ft/lb
Block Use: Any SBC Iron or Aluminum
Weight: 23 lbs Bare
* Photo for illustration purposes only
23 degree cylinder heads