This is a complete engine overhaul kit for Allis Chalmers tractors. Complete kits contain sleeves, pistons, rings, pins, complete gasket set, cam bearings, main bearings, and rod bearings. *Please specify bearing sizes when ordering* This kit is used on models B, C, CA, with the 125 CID 4 cylinder gas engine. This is a 3 7/16" overbore from the standard 3 3/8" bore.Be sure to add me to your ! Thanks For Your Business!!