ATK Core Return Process
JEGS and ATK appreciate your business and want to ensure that your core return is as smooth as possible.

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• Core return can be any Chevy LS 6.0L engine

Engine Specifications:

• Block: Seasoned 6.0L Iron Gen IV with ARP main studs
• Bore/Stroke: 4.030” x 4.000”
• Displacement (cu.in): 408
• Crankshaft: Manley 4340 forged 24 tooth reluctor wheel
• Rods: Manley 4340 forged H beam 6.125” ARP 2000 bolts
• Pistons: Manley 2618 forged -4cc flat top moly skirt coated
• Rings: Total Seal CS AP with steel top rings gapped for boost/nitrous
• Compression Ratios: 64cc = 11.9:1 / 68cc = 11.4:1 / 72cc = 11.0:1 (can vary due to deck height/gasket thickness)
• Camshaft Bearings: Installed & Clocked to OEM Position
• Freeze Plugs: Installed & Sealed
• Oil Galley Plugs: Installed & Sealed

Recommended Components:

• Balancer- Internal balance
• Flexplate/ Flywheel- Internal balance
• Head Gasket: .051” or per application
• Oil Pump: Melling #10295 with high-pressure spring

Engine Info:

• Oil: 10W30 Non-synthetic for first 3000 miles
• Oil Filter: Wix or K&N per application Notes: ATK’s Boost/Nitrous short blocks are meant for engines running these setups. Bearing clearances and ring gap have been taken into consideration for this series of short blocks.

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