SKU: NPR20-GNHM4005K8
MPN: 20-GNHM4005K8
The Perf. Piston Ring Set V8 4.005 Bore 1.2x1.5x3.0 is engineered for serious engine builders and performance mechanics who demand precision-fitted compression rings for high-displacement V8 applications. This NPR piston ring set addresses a critical need in engine rebuilds and performance upgrades: maintaining proper ring gap, blow-by control, and oil management in oversized or freshly bored cylinders. Whether you're restoring a classic big-block or assembling a modern performance engine, properly spec'd piston rings are non-negotiable for reliability and horsepower delivery.
The 1.2x1.5x3.0 ring geometry specifies the top compression ring thickness (1.2 mm), second ring thickness (1.5 mm), and oil ring rail thickness (3.0 mm)—dimensions that directly impact ring sealing efficiency and oil control under varying cylinder pressures. NPR's performance-grade construction utilizes advanced iron alloys and heat-treatment processes that resist scuffing, maintain dimensional stability across thermal cycles, and provide superior conformability to cylinder wall finish. The 4.005-inch bore dimension indicates these rings are sized for big-block applications, typically in the 427–454 cubic-inch range, where proper ring tension and seal quality become even more critical at elevated RPMs and boost pressures.
Mechanics and engine builders restoring fuel-injected, turbocharged, or naturally aspirated V8 engines will find this piston ring set ideal for applications requiring precise bore sizing and modern ring technology. Installation requires careful ring end-gap verification, proper piston groove cleaning, and use of a ring compressor to prevent damage during block assembly. Compatibility depends on your specific piston and block combination; verify bore diameter, ring groove widths, and manufacturer tolerances before ordering. For street, strip, or competition use, this NPR performance ring set delivers the sealing integrity and longevity that separates reliable powerplants from field failures.
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