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QUALITY STRENGTH PERFORMANCE SINCE 1981<br />
<strong>Dart</strong> PRO1 23° 227cc CNC heads are professional<br />
quality competition cylinder heads. We<br />
applied the airflow technology developed in our<br />
championship winning Pro Stock engine program<br />
to produce these state of the art heads.<br />
Every intake port, every exhaust runner, every<br />
valve bowl and every combustion chamber is<br />
100% CNC machined on special dedicated PRO1<br />
castings. These heads are ideal for high compression,<br />
big cubic inch small blocks and are<br />
great for supercharged applications.<br />
Standard valve angle and spacing are retained<br />
to allow use of off the shelf pistons and valve<br />
train components.<br />
Hardened exhaust seats are compatible with<br />
unleaded gasoline. Manganese Bronze valve<br />
guides extend cylinder head life.<br />
Heads are sold individually.<br />
23°<br />
227cc<br />
CNC<br />
QUICK INFO >>><br />
Maximum performance/full competition, unlimited<br />
oval and super classes. 7,000+ RPM, 400+ cubic<br />
inch engines.<br />
PRO1 23° 227cc CNC - ALUMINUM (Angle Plug Heads)<br />
66cc COMBUSTION CHAMBERS<br />
PART NO. CONFIGURATION FOR USE MAX. LIFT<br />
11970040P Bare Head<br />
11971142P 1.437” Dual Springs for Hydraulic Roller or Solid Flat Tappet Cam .620”<br />
11971143P 1.550” Dual Springs for Solid Roller Cam .700”<br />
SMALL BLOCK CHEVY<br />
CAST ALUMINUM CYLINDER HEADS<br />
The consistency and accuracy of CNC (Computer<br />
Numerical Control) machining makes every CNC<br />
ported <strong>Dart</strong> head virtually identical. Our automated<br />
5-axis machining centers port heads with incredible<br />
accuracy, and you get the performance benefits at a<br />
very affordable price!<br />
Head parts kit - see page 118.<br />
Uses 7/16” screw-in rocker studs.<br />
Assemblies with 1.550” valve spring<br />
use +.100” long valves.<br />
RECOMMENDED MANIFOLDS<br />
42411000 Single Plane<br />
42421000 Single Plane (4500)<br />
PRO1 23° 227cc CNC SPECS<br />
Material:<br />
RMR Cast<br />
Aluminum Alloy<br />
Valve Angle: 23° (stock)<br />
Intake Port Volume: 227cc CNC<br />
Intake Valve: 2.080”<br />
Exhaust Valve: 1.600”<br />
Chamber Volume: 66cc<br />
Plug Type:<br />
Angle<br />
FLOW DATA @ 28” WATER<br />
LIFT INTAKE EXHAUST<br />
.200” 158 123<br />
.300” 209 157<br />
.400” 257 187<br />
.500” 293 206<br />
.600” 302 221<br />
.700” 309 228<br />
.800” 324 235<br />
SHORT BLOCKS TOP KITS BLOCKS HEADS MANIFOLDS CRANKSHAFT ACCESS SBC LS BBC SBF HON COATINGS BILLET<br />
Not intended for sale or use with pollution controlled vehicles.<br />
248.362.1188 / DARTHEADS.COM Connect with us socially, search: DART MACHINERY<br />
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