I exchanged a '52 216 with a '57 235. On the front mount everything was missing except the mount; meaning the retainer, plate and shield.
You need you keep your 216 139 tooth flywheel from the 216 in order to use your original starter.
I would definitely use the water pump adapter plate - I like it better than the short shaft. I had to locate another fan blade with the correct center bore.
You may very well run into some throttle linkage problems but they are solvable.
I'm still running the 9" clutch from the 216 although I'm experiencing some noise when it's fully depressed, which in turn depresses me. Clankity clankity, like a throwout bearing but pretty sure it's the fork rattling around due to the clutch fingers not being fully depressed. Will confirm that soon as the engine is coming back out.
Finally, do a search of the Engine & Driveline shop on this topic and you'll find all of the information you need.
Don
