If you are really serious about running the engine you have on steam, research the live steam hobby. There are specialty suppliers around.
The engine you have is fairly large for most of the hobby. Steam boat (launch size) people use engines around 3 x 4 or smaller.
Here is a company that makes boilers for the steam boat hobby. http://www.tinypower.com/store.php?crn= ... =cat_click
Their largest boiler is too small for you. ($9600) The boilers come stripped. You still have to add insulation, piping, guages, controls, etc.
Don't forget about feedwater, chemcial treatment, load relief (what to do with steam once engine shuts down- usually pop saftey valve vented to safe location), etc.
Live steam and the public doesn't mix well and the insurance companies know it. All clubs I visit are usually low key and preach safety, safety, safety. They will have public invintational days occasonially and make very careful plans to deal with safety, safety, safety, safety safety, safety.