Hi Boxerbeat and welcome to our litle world
Powersteering can be changed to a normal steering rack, however you might need to change the whole steering column inside the car as well.
I changed a standard steering rack to powersteering on a Series 2 Ti. Had to chop off some of the firewall of the Ti for the powersteering to go in. Also had to change steering arms as well ( thicker - bigger holes ).
So that can be done the other way round as well.
Now a friend of mine is putting the powersteering of a series 3 33 on his Sprint.
He had to change the complete steering column inside the car and fabricate new brackets for the steering wheel.
So my guess here is that it's possible to do so, you will be left with a bigger hole where the steering rack attaches to the column inside, and maybe you will also need a spacer fabricated from the column to the rack as the distance is about 5cm further .
Early 33's did not have antiroll bar. Which one do you have ?