With ATK High Performance Chevy LM7 5.3L 385 hp long block crate engines expect big mid to upper end power and a noticeable idle. They were designed to be performance upgrades for a 1999-2007 Chevy truck LM7 or an LS swap in a hot rod.
Technical specifications include:
* Horsepower: 385+
* Torque: 390+
* Block: GM 5.3L iron LM7
* Bore/stroke: Up to 3.809 x 3.622
* Year range: 1999-2007
* Displacement: 323 c.i.d.
* Crankshaft: OEM GM 3.622 in. stroke internally balanced 24 tooth reluctor wheel .857 in. flange
* Connecting rods: OE GM forged powder metal 6.093 in. stock bolts
* Pistons: Hypereutectic dish
* Piston rings: Moly rings
* Compression ratio: 9.5:1 compression
* Camshaft: Hydraulic roller
* Camshaft specifications: Custom grind
* Camshaft bearings: Installed and clocked to OEM position
* Cylinder heads: OE aluminum 61.15cc 1.89/1.55
* Freeze plugs: Brass installed and sealed
* Rocker arms: OE powdered metal 1.7 ratio
* Oil Galley plugs: Installed and sealed
* Weight: 385