This 1200cc cylinder and piston kit contains a set of S&S 3-1/2" bore S&S cylinder with wrinkle black powder coat finish, fitted to a set of S&S 3-1/2" bore forged pistons for S&S Super Stock cylinder heads, head gaskets, base gaskets, and exhaust gaskets. When installed in 1200cc engines no flywheel balancing is required. If installed in an 883cc engine stock flywheel balancing is recommended. Compression ratio is 10.5:1.