SKU: ICNIC9986C.STD
UPC: 800745255808
MPN: IC9986C.STD
The ICON Pistons LS 5.3L Forged Piston Set delivers professional-grade performance for GM LS 4.8L and 5.3L engine builds. This complete set of eight 5.3 forged pistons features a 3.780-inch bore and minus 2.9cc flat top configuration, engineered specifically for engines running a 3.622-inch stroke with 6.125-inch rod length. Whether you're rebuilding a truck motor for improved durability or assembling a street/strip combination, these pistons provide the foundation for reliable power. Each set ships complete with wrist pins and Tru-Arc lock rings, giving builders everything needed to get rotating assemblies together without sourcing additional components.
ICON's Formed Head Relief design sets these pistons apart from conventional forgings. Rather than machining valve reliefs after forging, the relief pockets are formed directly into the piston during the forging process itself, maintaining material integrity in critical areas. The 4032 aluminum alloy construction contains 11% silicon content, which controls thermal expansion and permits tighter piston-to-wall clearances than lower-silicon alloys allow. This translates to reduced skirt and pin bore wear over the life of the engine. Ring grooves are cut for 1.5mm top, 1.5mm second, and 3.0mm oil rings, accepting industry-standard 5/64-inch compression rings and 3/16-inch oil rings. The 0.945-inch wrist pin diameter and 1.304-inch compression height maintain compatibility with stock-stroke rotating assemblies found in our engines and components category.
These 5.3 forged pistons and rods combinations serve builders running naturally aspirated street machines, tow vehicles needing upgraded internals, or weekend strip cars seeing occasional boost. The flat top design works well with factory-style combustion chambers while the forged construction handles the cylinder pressures that destroy cast alternatives. Pair this piston set with quality rod bearings and fresh piston rings for a complete rotating assembly refresh. We stock ICON products alongside other trusted brands for LS platform builds.
This piston set fits GM LS 4.8L and 5.3L engines using the factory 3.622-inch stroke crankshaft and 6.125-inch connecting rod length. The 3.780-inch bore diameter works with standard-bore blocks without requiring overboring.
The ring grooves are machined for 1.5mm top ring, 1.5mm second ring, and 3.0mm oil ring. In standard measurements, that translates to 5/64-inch compression rings and 3/16-inch oil rings, which are common metric-style ring packages for LS engines.
The 4032 alloy with 11% silicon content offers tighter piston-to-wall clearances and quieter cold-start operation compared to 2618. This makes 4032 ideal for street and street/strip applications where daily drivability matters alongside performance.
Each set includes eight forged pistons, matching wrist pins, and Tru-Arc lock rings. You will need to source piston rings, rod bearings, and connecting rods separately to complete your rotating assembly.
Formed Head Relief means the valve relief pockets are created during the forging process rather than machined afterward. This preserves the grain structure of the forged aluminum in critical areas, improving strength around the valve pockets compared to post-forging machining.
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