64mm very nice size for the mechanical guys with a little more fueling. These still tow very well and will have a better top end than the 60mm. 400-500hp can be seen pretty easily from this turbine.
67mm is by far the most common size we build with. They still perform well towing but allow for much more flow and fueling. These get put in many common rail units as well as a large portion of earlier 5.9’s. This is a great all around turbine where towing isn’t the emphasis of the build. I typically want this turbine on builds 500HP or better.