I've been trying to sort out the differences between water pumps and pulleys through the model years. I have an '85 600 ragtop with a 2.2 T1 and a 2.5 T1 on an engine stand that will eventually go in the car. From what I understand, the water pump and pulley of the '89 CB was an oddball and only used that one year. '90 had a bigger pulley bolt pattern. What I was wondering was if the pulleys from '90 and up cars had the same diameter and offset. In other words, if I put a '90 water pump/pulley on an '89 CB, will it play nice with the rest of the '89 belts and pulleys or do other things have to be changed?