You will find the codes for the correct bearings stamped underneath the block where the oil pan gasket is seated. You would need to use plastigauge to get a precise clearance measurement for the main bearings as well as connecting rod bearings. This is best done with the engine out of the car so that the weight of the crank doesn't throw the readings off. Plastigauge is available at most autoparts store. While you are at it, you should measure the crank endplay to ensure that the thrust bearings are good and don't need to be replaced. I would suggest getting a service manual for your specific application as they will cover all clearance measurements better than anyone here will.