This model can be used for lost-PLA casting or you could pour plaster in the shell and then make a reusable model for casting into sand. It's all up to you, just be careful with the molten aluminium. I recommend lost-PLA casting (melting model out of solid mold) because the model has no foundry bevels!
The size of the inner hole is 50mm. The cast cylinder will for sure need to be machined to create exhaustion and suction channels plus cylinder grinding to get the liner inside.