Summit Racing™ Chevy LS 5.3L 450HP Long Block Crate Engines SUM-150153

Buy Summit Racing™ Chevy LS 5.3L 450HP Long Block Online

Summit Racing™ Chevy LS 5.3L 450HP Long Block Crate Engine (SUM-150153) delivers big LS performance in a ready-to-install long-block package. Built from a seasoned OE LM7 5.3L iron block (323 cu. in.) and topped with OE aluminum #799/#243 heads, it’s rated at 450+ horsepower and 420+ lb-ft of torque—ideal for upgrading 1999–2007 Chevy/GMC trucks or powering an LS swap project. Inside you’ll find a Summit Racing Pro LS hydraulic roller cam, 10:1 compression with 5.3 long block hypereutectic flat-top pistons and moly rings, and a 24x crank reluctor, keeping Gen III compatibility.

The engine arrives assembled and machined by ATK, saving you time on machine work and build complexity; you simply add your intake, accessories, and supporting summit racing 5.3 crate motor components. Backed by a 2-year unlimited-mile warranty, it’s a strong value for street performance and drivability. Bore and stroke measure 3.800–3.820 in. by 3.622 in., with 2.00/1.55 valves for efficient airflow, plus responsive, aggressive LS sound.

Summit Racing™ Chevy LS 5.3L 450HP Long Block Crate Engines

Looking for big LS engine power at an affordable price? Summit Racing™ remanufactured 5.3L LS long block crate engines are rated at 450 HP and 420 lbs.-ft. torque! This engine will give you the performance and drivability you have been searching for at a price 5.3 liter long block you can afford. It can be a performance upgrade for 99-07 Chevy trucks, or an blueprint engines 383 engine swap into your project vehicle. You will save time and money by leaving the machine-work and assembly to us. Just bolt on your 5.3 l long block accessories and drop it in. These engines are machined and assembled for us by the guys at ATK, and backed with a 2-year unlimited mile warranty for peace of mind.

Technical specifications:

* Horsepower: 450+
* Torque: 420+
* Block: Seasoned OE LM7/5.3L iron
* Bore/stroke: 3.800-3.820 in. x 3.622 in.
* Year range: 1999-2007
* Displacement: 323 C.I.D.
* Crankshaft: OEM GM 3.622 in. stroke internally balanced 24-tooth reluctor wheel
* Connecting Rods: OE GM forged powder metal 6.093 in.
* Pistons: Hypereutectic flat top
* Piston rings: Moly
* Compression ratio: 10:1 compression
* Camshaft: Summit Racing Pro LS Roller
* Camshaft specifications: Lift- 550/550, Duration @.050- 222/232
* Camshaft bearings: Installed and clocked to OEM position
* Cylinder heads: #799 or #243 OE aluminum 64cc 2.00 in./1.55 in. valves
* Freeze plugs: Brass installed and sealed
* Rocker arms: OE powdered metal 1.7 ratio
* Oil Galley plugs: Installed and sealed

What does “long block” include?

A long block typically comes assembled with the block, rotating assembly, camshaft, cylinder heads, and valvetrain installed. You’ll usually supply items like the intake manifold, fuel system, exhaust, accessories, and other swap-specific parts.

Will it work with my 1999–2007 GM truck electronics?

This engine uses a Gen III 24x crank reluctor, which matches many 1999–2007 applications. Make sure your ECU/harness and sensor setup are compatible, and plan for proper tuning to achieve best drivability and performance.