Perf. Piston Ring Set V8 4.005 Bore 1.2x1.5x3.0

The NPR Performance Piston Ring Set V8 4.005 Bore 1.2x1.5x3.0 is engineered for serious V8 engine builders and mechanics seeking OEM-quality ring sets for stock or lightly modified builds. These rings are designed to fit 4.005-inch bore blocks, making them ideal for both original restorations and performance applications where precise bore sizing is critical. Whether you're rebuilding a classic big-block or refreshing a daily-driver V8, this complete eight-cylinder kit eliminates the hassle of sourcing individual ring sets and ensures consistent compression and blow-by control across all eight cylinders.

Constructed from premium nitride-coated steel, the Perf. Piston Ring Set V8 4.005 Bore features a three-ring configuration with 1.2mm top ring, 1.5mm second ring, and 3.0mm oil ring thicknesses optimized for standard tension applications. The nitride coating provides superior scuff resistance, extended durability, and reduced friction compared to uncoated alternatives—critical factors for engine longevity and baseline power retention. This standard-tension design maintains proper contact with cylinder walls under normal operating conditions, ensuring reliable sealing without excessive drag that could rob horsepower or accelerate wear on cylinder honing.

Professional rebuilders and experienced DIY mechanics favor NPR ring sets for their consistency and proven track record in American V8 engine applications. The 4.005-inch bore specification suits a broad range of displacement and platform combinations, and the compact shipping dimensions (5 x 2 x 9.5 inches, 0.75 lbs) make this kit convenient for mail-order delivery to your workshop. Installation requires proper ring-gap setting to the engine builder's specifications and careful piston-to-bore clearance verification—standard practice for any professional rebuild that demands reliable, repeatable results.