I am hoping to post some pictures of my project soon. I am in the process of buiding a half size working model of an Austin 7 engine. I have cast two small parts for the engine and they have come out reasonably well. But I always turn to the big parts and wonder how to cast them. The A7 engine has a separate block and crankcase. The block is cast iron, the crankcase aluminium. I am going to use aluminium for the block and head because I don't have the ability to melt iron. The block will require cast iron cylinder liners. I have 3D printed the block so I would have a physical object to examine. There are so many areas that should have draft that I thought it would be almost impossible to do at home. But, thanks to watching many youtubers videos I have a cunning plan. I will produce a new 3D print with no draft and take a rubber mould from it. I will then use the rubber mould to either produce a wax pattern or an easy to melt metal (pewter?) pattern. This pattern will then have some kind of investment shell and when fully set, the pattern can be melted out. I can then use the shell to produce an aluminium casting with no draft. I hope to learn more from this site to see if I am on the right track. I will try casting the cylinder head using greensand, but there is no draft on the pattern so it might not pull from the mould cleanly. Both the head and block also have a water core.