ATK Core Return Process
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This ATK 383 stroker engine built for the ruggedness for high-performance street and strip applications producing great power and a lopey idle. Completely assembled with a matched intake, distributor, carburetor, water pump, balancer, fuel pump, spark plugs, and wires to eliminate any guesswork.

NOTE:

• Core return can be any Small Block Chevy 350ci engine, except 1992-1997 LT1 style engines
• This engine will not work in vehicles with power brake or air conditioning 

Engine Specifications

• Horsepower: 525 hp
• Torque: 515 ft.-lbs.

Block Information:

• Seasoned OE 4-bolt main 1pc seal 
• Bore/Stroke: 4.040 in. x 3.750 in.
• Displacement: 383 ci
• Brass freeze plugs

Rotating Assembly:

• Crankshaft: Scat 4340 forged
• Balance: External rear, internal front
• Rods: Scat 4340 forged H-Beam 5.700 in. with ARP 8740 bolts
• Compression Ratio: 10.0:1
• Pistons: Forged
• Rings: Moly

Camshaft Specs:

• Camshaft: Hydraulic roller
• Cam Duration @ .050 in.: Intake 246 / Exhaust 250
• Cam Lift: Intake .603 in. / Exhaust .609 in.
• Lobe Separation Angle: 110 LSA
• Timing Chain: Double roller

Cylinder Head Information:

• Cylinder Heads: ATK Pro-Filer Aluminum
• Combustion Chamber: 70 cc
• Intake Runner: 210 cc
• Valve Size: 2.050 in. Intake / 1.600 in. Exhaust
• Rocker Arms: Biller aluminum roller rockers 1.6 ratio

Oil Pan Information:

• Oil Pan: Moroso Rear sump 7 qt with windage tray
• Oil Pump: Melling standard volume

Complete Engine Includes

• Short Block
• Camshaft
• Timing Set
• Cylinder Heads
• Valve Covers
• Timing Cover
• Oil Pan
• Oil Pump & Pickup Tube
• Flexplate 168-tooth
• Intake Manifold Single Plane Holley Strip Dominator
• Distributor Pro-Billet 
• Water Pump Long style
• Harmonic Balancer Internal
• Fuel Pump Holley Mechanical 110 gph
• Carburetor Quick Fuel 750 cfm
• Spark Plug Wires 
• Spark Plugs Autolite 

Recommended Engine Components

• Exhaust: 1 3/4 in. Headers
• Firing Order: 18436572
• Fuel Octane: 91+
• Stall Converter: 3000+
• Oil: 10W30
• Oil Filter: Wix or K&N
• Timing: 34-36 Degrees

Disclaimer: The parts listed are ATK's recommendations of parts to be used to obtain the power figures listed. Power figures can vary based on parts used by the end-user. Some modifications to the vehicle may be required using these and or other aftermarket parts.

Engine Break-In Procedure

Use or break-in oil or conventional (non-synthetic) 10w30 oil with zinc additive for the first 500 miles of operation.  Do not drive for long periods at any single speed, always vary your speed. Do not tow a trailer or put other heavy loads on the vehicle. It is best to avoid long periods of idling during this period. Check the engine oil and coolant levels daily. 

Engines with flat tappet hydraulic cams only - Run the engine between 2,000 and 2,500 RPM's, with no-load on the engine for the first 30 minutes. Let the engine cool down completely and repeat the process 2-3 more times. Do not idle the engine for an extended period at this time, this is critical to break in the camshaft.

At 500 Miles change the engine oil and filter using conventional (non-synthetic) oil with a zinc additive. Check fuel and ignition settings, adjust valves (where applicable).  Drive the next 500 miles normally, without high RPM's (below 5000 RPM), hard use, or extended periods of high loading or long periods of idling.

Change the oil and oil filter again at 1,000 miles. Continue using conventional (non-synthetic) oils and zinc additive, until about 4,000 miles. At that point, you may run a quality 10w30 synthetic oil if you choose. Use of oil with zinc or a zinc additive for the life of your engine is recommended. 

Emissions Note:

This part is only legal for sale and use on Uncontrolled (Non-Emissions Controlled) Vehicles or on vehicles used solely for the purposes of closed competition racing.

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