Belt size for air conditioning pump bypass?

Because of the routing path on that engine there isn't a way to bypass the AC compressor using just a shorter belt as the water pump wouldn't drive properly because it wouldn't touch it's drive sheave. As such you need a bypass pulley kit like the Dorman 34197, it bolts on in place of the AC compressor and you use the original belt. I used a newer image of the 3.1 but the belt routing is the same, your compressor just bolts onto the face of the engine cover rather than the side. The bypass pulley bolts on the same way. You unbolt the AC nd secure it out of the way.