High Performance Crate Engine GM LS 383ci 515HP / 505TQ

Name: High Performance Crate Engine GM LS 383ci 515HP / 505TQ
Brand: ATK ENGINES
SKU: 059-LM7-LB-3
Price: 8133.31 USD
Availability: InStock

^$8,133³¹

Core Charge: ^$285⁰⁰

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Ships on 11/06/2026

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GM LS 383ci
5.3L LM7 Block Bored and Stroked
515HP / 505TQ
Base Engine

Engine Info
Recommended Components
Notes: This engine can replace the 1999-2007 Chevy 5.3L LM7 engine with supporting modifications or any other factory LS equipped vehicle. It can also be retrofitted for an aftermarket EFI/Carb setup. ECM must be tuned, not doing so can damage the engine.
Disclaimer: 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 conventional or break-in oil (non-synthetic) for the first 600 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. Check the engine oil and coolant levels daily.
At 600 Miles change the engine oil and filter using conventional (non-synthetic) oil. Check fuel and ignition settings; adjust valves (where applicable).
After the first 5,000 of service synthetic engine oil may be used. Follow your vehicle owner’s manual for service intervals.
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
Please CLICK HERE for ATK Warranty

In 2007, ATK launched a High Performance Division with one of the finest engine shops in the country. By reverse engineering all of their engines, they are able to eliminate any OEM deficiencies. This makes an ATK built crate engine have a superior design over the original engine by incorporating better components when needed. These quality built engines are offered in three different stages for ease of finishing an engine swap. ATK HP engines feature a 24 month/unlimited mile warranty.

Engine Specifications

This is an LM7 based engine with CNC ported cathedral port aluminum heads making a very street able 515hp. Expect big mid to upper power, will have a noticeable idle. For optimal performance you will need headers, chassis dyno tune, and upgraded injectors.

Horsepower: 515 hp
Torque: 505 lb/ft

Block Information:

OE LM7/5.3L iron
Bore/Stroke: 3.903" x 4.000"
Displacement: 383ci

Rotating Assembly:

Crankshaft: K1 4340 forged 24 tooth reluctor wheel
Rods: K1 4340 forged I beam 6.125" with ARP 8740 bolts
Compression Ratio: 10.3:1
Pistons: Wiseco forged
Rings: Moly

Camshaft Specs:

Camshaft: Hydraulic roller
Cam Duration @ .050": Intake 218 / Exhaust 224
Cam Lift: Intake .604" / Exhaust .604"
Lobe Separation Angle: 112lsa

Cylinder Head Information:

Cylinder Heads: OE aluminum CNC ported cathedral port, dual valve springs, and titanium retainers
Valve Size: 2.02" Intake / 1.60" Exhaust
Rocker Arms: OE 1.7 ratio
Timing Chain: Billet HD .250" roller

Oil Pump Information: