Chev 305 Mahle Original Standard Piston Ring Set # 51752CP.STDPiston Rings, Standard Piston Ring Sets, Cast Iron, 3. 736 in. Bore, 5 64 in., 5 64 in., 3 16 in. Thickness, V8, Set Bore (in.): 3. 736 in. Bore (mm): 94. 894mm File Fit: No Gapless: No Gas Ported: No Top Ring Included: Yes Top Ring Thickness: 5 64 in. Top Ring Material: Cast iron Top Ring Facing Material: Cast iron Second Ring Included: Yes Second Ring Thickness: 5 64 in. Second Ring Material: Cast iron Second Ring Facing Material: Iron Oil Ring