Charts are references to Breathing Better Caption.
|Dart 23-degree Iron Eagle Cylinder Head |
|Combustion chamber ||64 cc |
|Intake port volume ||180 cc |
|Exhaust port volume ||77 cc |
|Intake/Exhuast valve ||2.02/1.60 inches |
|Valve springs (dual) ||1.437 inches in diameter |
|FLOW FIGURES |
|LIFT ||INTAKE ||EXHAUST |
|0.200 ||139 ||114 |
|0.300 ||193 ||145 |
|0.400 ||231 ||164 |
|0.500 ||249 ||172 |
|0.550 ||253 ||173 |
Breathing Better Up top we...
Up top we utilized a Dart top-end package. At just $1,600 this kit was a no-brainer and comes complete with head and intake gaskets, only requiring a set of head bolts.
At the front of the block,...
At the front of the block, each assembly comes with recessed front oil galley pipe plugs. This is to make sure the timing chain and gear do not wear into each other. These kits also come with coated cam bearings.
At the foundation of the beast...
At the foundation of the beast are four-bolt mains. You'll notice that main caps No. 2 through No. 4 are splayed for better clamping force. The rotating assembly features a cast steel 3.480-inch crankshaft and forged 4340 I-beam rods with 3/8-inch cap screws. Clevite bearings reside throughout the short-block, with Hastings Moly rings surrounding each piston.
Our 'stick of choice was a...
Our 'stick of choice was a Comp Cams hydraulic flat-tappet featuring 230/236 intake/exhaust duration at 0.050 with lift numbers at 0.490/0.490 intake/exhaust on a 110-degree lobe separation.
We buttoned up the front with...
We buttoned up the front with a Comp Cams double-roller timing chain and gearset. We also used a bit of Loctite on the front cam bolts and finally torqued them down to 28 ft-lb.
While it isn't required, we...
While it isn't required, we used a Comp two-piece timing cover to facilitate future testing. This will make cam swaps easier since the front plate is detachable and we won't disrupt the front oil pan seal. Before installing the cover, we placed the gasket on the base plate and added silicone on top of the plate.
Next, we placed our Fel-pro...
Next, we placed our Fel-pro head gaskets (supplied with Dart top-end kit) and set the Dart Iron Eagle heads onto each bank. Using some Moly-lube on the head bolts, we dropped in each bolt and torque them down to 70 ft-lb in a clockwise manner, starting at the center bolt.
After determining that we...
After determining that we would need a 7.800-inch pushrod to complement our Comp Gold 1.5:1 roller rockers we could begin to install each one. Westech's Steve Brul locked each rocker down and lashed it to 0.16/0.18-inch intake/exhaust cold.
Dart SHP 372 1. With minimal...
Dart SHP 372
1. With minimal jet changes, the Street Avenger 770 performed flawlessly. It's a steal, too, at $449.
2. To expel the exhaust, we strapped on a set of 13/4-inch diameter hooker headers with 18-inch collectors.
3. The Comp two-piece timing cover allows for easy cam swaps. Inside sits a Comp double-roller timing chain, gears, and a 230/236 Comp hydraulic flat-tappet cam.
4. Dart supplies everything in its top-end kit, including its dual-plane manifold, which helps to produces great bottom-end torque for everyday drivers.
5. Our Dart 180cc Iron Eagle heads are a bargain. They come fully assembled with springs (we ordered dual springs), head gaskets, and head bolts.