Mark,
If they are 120/104's, you may not like those if you are looking for max torque & smoothness below 6K. Those do best between 5K and 7400 in a 3.0.
4-bearing cams cannot be used in 3 bearing cam housings but 3 bearing cams can be used (in a pinch) in 4 bearing housings.
I would recommend getting the right cams for your engine and type of use.
