I also want to create model cars with working parts but trying to find drawings of cars with all of the parts (engine, transmission, suspension, etc) is like trying to find needle in haystack. I already printed working engines and transmissions that I find at Thingiverse but I can't find model cars with working parts. In 1960s, there was Visible Auto Chassis and I had one but the company stopped making the chassis and today's Visible V8 doesn't have "spark plugs" and starter motor that runs the engine. Almost all of the plastic model car kits are two-doors with powerful engines, bucket seats, consoles, and floor-mounted shifters.