[rotorwrench]

I'm assuming that this is a model F. The Fordson House would be a place to start. There are a lot of tractor specific collectors out there and they tend to horde parts for their collections.

The model F manifolds are thin castings so they do like to crack. A good welder might be able to repair the set but it would be difficult. I think that they were reproduced at one time but I'm not sure now. Google as far as you can go with model specific parts. A lot of these were kerosene burners but I think that they were converted on some cases. They are cantankerous old turds and can be hard to start. The magneto section of the flywheel and the rest of the coil ignition set up is a lot like a Model T so a person needs to learn up on the trembler coil systems like the model T to make sure they are in top shape for starting. A conversion to gasoline may help with starting if not so equipped but I think that they had a small part of the tank with gasoline in it for starting.

While checking around, I noticed one that had an engine driven magneto but I have no information on that.