
High-Performance Short Block GM LS 408ci
This product is currently not available. Please call customer service for assistance at 1-800-345-4545.
ATK Core Return Process
JEGS and ATK appreciate your business and want to ensure that your core return is as smooth as possible.
Please CLICK HERE for ATK Core Return Process
- Core return can be any Chevy LS 6.0L engine
Engine Specifications:
- Block: Seasoned 6.0L Iron Gen IV
- Bore/Stroke: 4.030” x 4.000”
- Displacement (cu.in): 408
- Crankshaft: Manley 4340 forged 58 tooth reluctor wheel
- Rods: Manley 4340 forged H beam 6.125” ARP 8740 bolts
- Pistons: Manley 2618 forged -29cc dished moly skirt coated
- Rings: Plasmamoly
- Compression Ratios: 64cc = 9.3:1 / 68cc = 9.0:1 / 72cc = 8.7:1 (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
- Flex plate/ Flywheel- Internal balance
- Head Gasket: .051” or per application
- Oil Pump: Melling #10295 with high-pressure spring
Engine Info:
- Oil: 10W40 Non-synthetic for first 3000 miles
- Oil Filter: Wix or K&N per application
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.
CLICK THIS LINK FOR IMPORTANT CARB & EPA EMISSIONS INFORMATION ABOUT THIS PART
![Engine Assembly Lube [4 oz. Bottle]](https://www.jegs.com/images/mini_200/500/555/555-28000.jpg)

![Engine Stand [1250 lb. Capacity]](https://www.jegs.com/images/mini_200/500/555/555-80041.jpg)
![Break-In/Engine Oil Supplement [12 oz. Bottle]](https://www.jegs.com/images/mini_200/500/555/555-28060.jpg)