Perf. Piston Ring Set V8 4.005 Bore 1.2x1.2x3.0

The NPR Perf. Piston Ring Set V8 4.005 Bore 1.2x1.2x3.0 is engineered for high-performance and rebuild applications in big-block V8 engines requiring precision ring fitment. Whether you're restoring a classic muscle car, performing a complete engine rebuild, or upgrading worn ring sets in a performance platform, this NPR ring set delivers the compression sealing and durability required for reliable operation. Purpose-built for 4.005-inch bore diameters, these rings maintain critical ring gap tolerances and contact geometry essential for modern engine demands.

Each ring in the 1.2x1.2x3.0 configuration—top, second, and oil ring thicknesses—is manufactured to OEM-grade specifications that ensure proper blowby control, oil consumption management, and ring-to-groove clearance consistency. NPR's performance-grade construction utilizes advanced iron alloys and precision honing to maximize gas sealing while minimizing friction losses, a critical factor in maximizing horsepower and fuel efficiency across the rpm band. The 3.0mm oil ring thickness provides superior oil return and scraping capability, reducing crankcase pressurization and extending engine longevity during high-load operation.

Mechanics and engine builders working on 4.005-bore platforms—including late-model big-block and stroker applications—rely on NPR ring sets for consistent honing clearances and repeatable assembly results. Proper installation requires accurate bore measurement and honing to specification; this ring set is compatible with standard V8 piston designs featuring corresponding 4.005-inch bore diameters. During rebuild, verify ring end gaps and groove clearances per manufacturer specifications to ensure optimal sealing and minimize wear on newly bored or machined cylinders.