Perf. Piston Ring Set V8 4.165 Bore 1.2x1.5x3.0

The Perf. Piston Ring Set V8 4.165 Bore 1.2x1.5x3.0 from NPR Piston Rings is engineered for high-performance V8 engines requiring precise ring geometry and reliable sealing at elevated boost pressures and RPMs. This ring set addresses the critical need for engines with 4.165-inch bore diameters—common in custom builds, stroker modifications, and competition applications—where OEM rings may not deliver the performance characteristics demanded by modern fuel injection, turbocharging, or naturally aspirated builds. Builders and engine shops trust NPR's proven reputation for manufacturing rings that maintain compression integrity while reducing blowby across extended operating ranges.

This piston ring set features a three-piece configuration with dimensions of 1.2mm top ring, 1.5mm second ring, and 3.0mm oil ring—a proven stack that balances compression retention with acceptable friction losses in performance V8 applications. The 4.165-inch bore specification ensures precise fit in custom-bored blocks or aftermarket cylinder sleeves, critical for achieving proper ring-wall contact pressure and minimizing oil consumption. NPR's manufacturing process employs high-carbon steel materials with controlled gap tolerances, enabling consistent performance across temperature extremes and preventing ring stiction or excessive wear that plague inferior ring sets in boosted or high-revving engines.

Engine builders specializing in LS platforms, big-block Chevrolets, and large-displacement V8 strokers benefit most from this ring set's dimensional precision and durability under sustained high-load conditions. Installation requires careful bore cleaning, proper ring end-gap verification, and accurate piston-to-wall clearance measurement—standard procedure for any bottom-end rebuild but especially critical with performance rings. Verify your engine block's current bore diameter and piston configuration before ordering; NPR's 4.165-inch specification suits custom-honed blocks in the mid-large-displacement range and delivers measurable compression gains and reduced blowby versus worn OEM rings or substandard aftermarket alternatives.