This is a 2.5cc gas RC engine. This is also a complete parts motor that I have been working on for some time now. Some parts need supports and others you can get away with not using any supports, I'll leave that up to you. You will need to sand the parts down to fit so the better your 3D Printer is calibrated the less you'll need to sand. Have fun with printing this if anyone will that is. Mine is printing right now and I'll update it with photos when I'm done.