Can anyone tell me the purpose of this part? it has a nipple at one end which fits into the rear of the passenger side exhaust manifold, and an open cup at the other end which sits above the valve cover.

 

It is the hot air choke stove for the choke on the carb. The 215 doesn't have an exhaust crossover under the carb, so this is where the hot air came from to operate the bimetallic coil in the choke housing.

 

There should be a filter in the cup. The other end plugs into a port on the right side exhaust manifold between the head and the firewall.

 

I don't understand how it works the choke?? It's connected to the exhaust manifold on one side and vented to the atmosphere on the other. It doesn't connect to the carb in any way.
The pipe for the choke exits the choke housing and taps into the same manifold between no'4 and no' 6 cylinder

 

Iron: I agree with your comment about the pipe between the choke and the manifold, but what is the purpose of the pipe with the cup at the end.. and what type of filter does it need?

 

As far as I can tell It was some sort of vent pipe. The parts books only list it as "pipe" with a part no. and a separate no. for the filter.
If you look at the right side exhaust manifold there should be two ports on it.

 

I looked in the repair manual and it lists it as a "Choke air inlet pipe"????
I personally never saw this setup on any other car. I wonder if they used it on Specials and Skylarks.