The biggest Big Bore possible with a slip in kit! The S&S 4.320" bore cylinder kit takes your 107" M8 to 129" and the 114" to 132".

• Huge bore increase means huge power increase 
• Works with stock crankcases (no machine work) 
• Powder coat finish matches factory finish, 
• MLS (multi-layered steel) head gaskets 
• 4.320" Bore 
• Retains stock engine height 
• Includes Cubic Inch Cam Cover Badge