There should be a number stamped on your rod, and a letter on the crank which will help determine what size bearing you need. For example, a red bearing would mean that your rod is stamped with a 1, and the crank with an A or an I. If you can tell me the number on your rod, and the letter on the crank corresponding to that rod, then I can tell you what color bearing you need. If these are aftermarket rods, or if you're not sure which cylinder the odd bearing is from, then you'll probably have to check the clearance with plastigauge and figure out what bearing you need.