Dart 370 Cnc Race Series Big Block Chevy Cylinder Heads on 2040-parts.com

Brand New Dart 370 CNC heads that have been black chromate coated by Dart for corrossion resistance.
They are being sold bare and the price you see in the buy it now is for a PAIR of heads.

Dart big block heads deliver superior performance without the hassles of welding and modifying stock castings. We applied proven Pro Stock technology to produce big block heads that out perform the competition - yet Dart heads can be used with most off the shelf pistons, manifolds, headers and valve train components.

Features:

• Premium alloy: Dart aluminum heads are cast from virgin 355-T61 aerospace alloy for superior strength and integrity.
• Shallow combustion chamber design improves combustion and allows use of larger valves for improved airflow.
• Interlocking ductile iron valve seats are compatible with stainless steel and titanium valves.
• Spark plugs are shifted toward bore centerline to enhance flame travel and reduce spark advance requirement.
• Refined intake port design reduces turbulence and increases air/fuel flow.
• Optional spread exhaust ports allow use of larger primary tubes without header plates.
• Water passages between exhaust ports improve cooling and prevent "hot spots" that can cause head gasket failure.
• Gasketed 3/4" reach spark plugs offer widest selection of heat ranges.

Specs

Dart 370 BBC Aluminum Cylinder Head
Material: 355T6 alum alloy
Comb Chambers: 121cc w/CNC)
Intake Valve Dia: 2.300”
Intake Port volume: 360 sm-366cc
Intake Port Dim: 1.750” x 2.500” (S/M & F/P)
Int Port Location: Stock
Intake Gasket: Mr Gasket# 121
Exh Valve Dia.: 1.900”
Exh Port volume: 143cc
Exhaust Port Dim: 1.600” x 1.900”
Exh Port Location: Raised .300” Std bolt pattern
Exhaust Gasket: Fel-Pro 1412 -Mr Gasket 5914 (F/P)
Exhaust Bolts: 1” longer than stock (4) ea.
Flow, Intake: 360 - 377 cfm @ .750 lift/28” (our valve = +10/15cfm) 360 - 399 cfm @ .750 lift/28”
Flow, Exhaust: (S/M) 255 cfm (F/P) 280 cfm @.750 lift/28”
Head Bolts/studs: Bolts – ARP# 135-3603 Studs – ARP# 235-4103
Manifold: Rect. Port Dart (opening - 1.575”x 2.250”) 6.25” tall
Milling: Min. 105cc / .070” (.005” = 1cc) Flat mill only.
Pistons: Most aftermarket pistons.
Push Rod length: Avg. +.200” / +.250” Should always measure
Stock length Int. = 8.275” / Exh = 9.250”
Push Rod Guide Plate Dart BBC Adjustable Guide Plate
Retainers: Titanium 10°
Spark Plug: .750” reach, gasketed. Autolite AR3933, Street AR3924 (AR133 for pre-1999)
Spring Cups: 1.625” - .035 cup / 1.550” - ID locator
Spring Pockets 1.740” OD for 1.625” cup (.030” deeper max)
Springs: Our Assembly: 1.550S = 145# @1.900” / .660” max Comp 936
1.550D = 195# @ 1.900” / .690” max Comp 954
1.625D = 250# @ 2.000” / .790” max Vasco-Jet H-11
Valve Angles: Int - 24°, Exh - 15° (Rolled 2°) 4° cant
Valve Length: Int - 5.475” (+.250) Exh - 5.435” (stock)
Valve Stem Dia: .3415” -11/32”
Valve Train: Std BBC 7/16” stud mount
Valve Guides: 1/2” OD Mag - bronze Cut for .530” PC seals (.002” press)
Valve Guide length: Int - 2.100” Exh - 2.250”
Valve Guide clearance: .0014” - .0021” (with our .3415 dia. valve stem)
Valve Guide Spacing: Exh moved .045” away from Int
Valve Seats: Powder metal, .006” press (TIR .004)
Valve Seat dim. Int. - 2.450” x 2.000” x .375” Exh - 2.000” x 1.600” x .375”
Valve Seat angles: Int = 32° - 45° - 60° - 70°-80° Exh = 37° - 45° - radius
Stud Girdle: Must use DART design. Part# 64110001
Torque: Head Bolts = 70 ft/lb Rocker Studs = 45 ft/lb
Manifold = 35 ft/lb Dart inner head studs 3/8-7/16 = 50 ft/lb
Block Use: Mark IV, Gen V, Gen VI with proper head gasket
Weight: 74 lbs