Matt King, Jackson, Mississippi
1985 Yellow IROC-Z
Specifications:
Displacement: 331 cu. inches (327cu. inch – bored .30 over)
Horsepower: 300 @ 5200 RPM
Bore & Stroke: 4.0315" X 3.25"
Compression Ratio: 9.15:1
Crankshaft: 3.25” Stroke GM Cast
Connecting Rods: GM Modular
Pistons: TRW Cast 5/64 x 5/64 x 3/16 package
Piston Rings: Molly top, Iron 2nd, Std tension oil
Camshaft: Milling # 22200 Lift .447 Duration 290 duration @50 – 222
Valve Lash (Intake/Exhaust): Zero
Cylinder Heads: #624 GM Iron cut to 72 cc’s
Intake Valve: (1.94")
Exhaust Valve: (1.50")
Valve Springs: RV943X 100#s @1.750”
Rocker Arm Ratio: 1.5:1
Crankshaft Thrust: .011”
Rod Vertical Clearance: side .016”-020” oil .0015” - .0025”
Main Oil Clearance: .0025”
Skirt Clearance: .0025” - .003”
Top Ring End Gap: .017”
2nd End Gap: .013”
Carburetor: 750cfm chrome Holley four-barrel w/ vacuum secondaries
Intake Manifold: Stock aluminum – ’85 Z28 H.O. 305cu.
Distributor: High Energy Ignition with centrifugal and vacuum advance
Initial Spark Setting: 10 degrees @ 800 RPM with vacuum advance disconnected.
Maximum Recommended Engine Speed: 6000 RPM
Fuel Requirement: Premium Unleaded (93 Octane)