106-5520 3-1/2" bore 9:1CR piston kit. +.010"

This S&S forged piston kit is designed for 1979 to 1984 1340cc Shovelhead engines and provides a performance-oriented 9:1 compression ratio. These are .010 inch oversize pistons with a 3-1/2 inch bore, intended as a direct replacement for stock units while offering a bit more compression for improved power. The advanced forged alloy and skirt profiles ensure quiet operation and exceptional durability. Sold as a set, the kit includes wrist pins, clips, and rings. It is important that a knowledgeable mechanic installs these components and verifies all clearances to ensure the engine runs reliably throughout its life and follows proper break-in protocols.