Hi Mike
I posted the drawing for the 325/335 hydraulic cylinder on this site two or three years ago, I think it is still accessible. If not let me know and I will post it again.
This is not the same as the P31 ram because the keel system is significantly different.
There is nothing special about 325 clyinder apart from the fact that the bar is made from 316 stainless. There are lots of hydraulic suppliers who could make you one but it would definately be worth researching getting it rebuilt first.
Good luck
Martin
P335/50