Hi all,I hope to be starting my 1/3rd scale model of a 1930 Austin Seven engine soon......Step 1. I am now fairly proficient at using the cad programme FreeCAD. It has annoyed the socks off me on dozens of occasions, but I couldn't stop using it even though I have a new copy of Solidworks, I still prefer to use FreeCAD. I have now designed the block and the head, I hope to attach images, if I get them in the correct order the first image will be of the block with a white outline at the front. The outline is the sketch I use to "cut" into the block to show the internals. Other images are sections of the block. The last two images show the inlet and exhaust ports moulds. They will need to be lengthened to give more material on the valve face and the ports face. My explanations are poor, forgive me! One of the ports images has a great deal of lines on it, this is the file that could be sent to a 3D printer.Step 2. 3D printing of the moulds. If I cast the parts in aluminium then I can 3D print the block as it appears and use investment plaster to produce the mould. The 3D printed part is the melted out and metal poured in. If I have to pour in aluminium, very likely, what type of finish would be suitable? I would prefer it to look like cast iron, perhaps a matt black would give it a display model look that would be OK. Your advice and oppinions requested please.I will stop here as there are more steps for another day.Lee