The only experience I have had is with a Lely Roterra power harrow in sandy loam soil. The one thing that I do know is they do not like rocks even though the advertising says/shows that rocks are no problem. Rocks do wear the machine much faster than clean, rock free dirt! That being said, if the clay clods will break by striking them with a hammer or some other object, I would think the power harrow would do a good job, and you can control the amount of pulverizing by your speed, to a certain extent. In no way will you get the clods broken down to powder, but it will be a mix of powder and smaller clods. I don't know what kind of machine you have available to you--depending on the manufacturer, there are different kinds of rollers on the back of some of the power harrows that will assist in pulverizing the clods. Your 155 horsepower should be adequate, depending on speed and depth. If it is a new machine that you use, be sure to check the tightness of the nuts that hold the tines in the tine holders (if they are held in by nuts), after running an hour, and if some are loose, recheck it again in another hour. If it is a borrowed/rented machine, check the tine tightness initially and again in an hour. Be sure to read the owner's manual for initial machine setup, lubrication, and maintenance.

Below is a video of a Kuhn power harrow and a Kuhn rototiller in action. The rototiller would probably get you more pulverization, but they are power hungry!

https://www.youtube.com/watch?v=ErMz7BLajZE

https://www.youtube.com/watch?v=iAggV6377c4

Good luck with your project!