MAHLE 930022790 Forged Piston Bore Alloy Dish - 521cid 4.390 4032 8.6cc

The MAHLE 930022790 is a high-performance forged piston designed for 521 cubic inch big block applications. Manufactured from 4032 aluminum alloy, this piston offers exceptional strength, low thermal expansion, and outstanding durability under high-load, high-heat racing and performance conditions.

Key Specifications:

• Bore Diameter: 4.390 inches
• Compression Height (CH): 1.345 inches
• Stroke: 4.300 inches
• Rod Length: 6.800 inches
• Pin Diameter: 0.990 inches
• Dome/Dish Volume: -8.6cc (dished)
• Piston Weight: 615 grams
• Compression Ratio: 11.4:1
• Alloy: 4032 forged aluminum
• Displacement: 521 cubic inches

Why 4032 Alloy?

MAHLE's 4032 alloy formula features a higher silicon content compared to 2618 alloy, resulting in lower thermal expansion and tighter piston-to-wall clearances. This translates to quieter cold starts, reduced cylinder wall wear, and excellent longevity — making it the preferred choice for high-compression street/strip and endurance racing applications.

The -8.6cc dish design works in conjunction with your combustion chamber and head gasket to achieve the target 11.4:1 compression ratio, optimizing power output for pump premium or race fuel applications. At just 615 grams, this piston delivers an excellent strength-to-weight ratio critical for high-RPM performance builds.

MAHLE Motorsports is a globally recognized leader in OEM and performance piston technology, supplying top professional racing teams and performance engine builders worldwide.