LS ASYM FT

The JE Pistons 311963R is a set of flat top pistons designed for GM LS Gen III/IV engines with a 4.010 bore. These pistons feature an Asymmetrical FSR (Forged Side Relief) forging design that offers a larger skirt on the major thrust side and a smaller skirt on the minor thrust side to reduce friction. They are constructed from 2618 forged aluminum for high strength and durability.

Machined for 1.2mm, 1.5mm, 3.0mm rings, these pistons include accumulator grooves, double pin oilers, and an offset wrist pin. The compression ratio varies based on the cylinder head volume: 10.6:1 for 64cc heads, 10.2:1 for 68cc heads, and 9.9:1 for 70cc heads.