Based on a set of plans written in 1906. It will be cast of Aluminum as soon as there isn't water everywhere. A core box will also be made for the cylinder cavity and combustion chamber core.
@Martin Aislabie The fins are going to be the hard part. Thinking about it, near the parting line the sand would practically have to slide sideways on the fin, making the draft angle zero. I have a feeling this will require a lot of fine tuning. I would start now but I just went outside and found my plastic tub of greensand had a hole in the lid. Consequently the greensand was at the bottom of a block of ice. This may take some waiting.