Engine Kits

Perfect Circle 40564CP40 Moly Ring Set 4.040" bore 350 .040 Oversize
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Perfect Circle 40564CP40 Moly Ring Set 4.040" bore 350 .040 Oversize

Part #: 40564CP40
List Price: $66.22
Our Price: $32.16
You Save: $34.06

350 Chevy Moly Ring set .040 Oversize
4.040" bore
5/64 5/64 3/16 Grove Size

Steel Compression Rings Replacing Cast Iron Rings

The advantages of the carbon steel include 35% more strength, 30% less weight due to smaller radial wall thickness and double the resistance to side wear, which is a common problem on late-model engines.

Since the steel is 35% stronger than cast iron, the rings can achieve the same ring tension with 35% less weight. The weight savings is accomplished by reducing the radial wall thickness of the steel ring. The result is a ring that's lighter, with a higher effective RPM potential and stronger to survive the abuse of today's high output engines. The material change also allows the ring to seal better due to the reduced radial wall allowing it to conform to the cylinder wall better.

MAHLE, manufacturer of Perfect Circle® piston rings, is the largest manufacturer of piston rings in the world, leads the way in ring technology and innovation. Perfect Circle rings are at the forefront of both light and heavy vehicle piston ring technology. Extensive OE connections mean that Perfect Circle rings have the technological edge. Things like the CP-20 oil ring, narrow compression rings, steel compression rings for gasoline engines, low tension oil rings and coated compression rings for diesels all came from the OE. Now, MAHLE’s rededication to the Perfect Circle performance line proves that Perfect Circle should be the ring choice under every hood - regardless of the application.