Tesla Motors Club

The previous owner of our house had 2 40A circuits going to a dedicated garage junction box. Based on what other items I saw laying around, I think he was growing cannabis. This is in CO so it's legal to grow the sticky icky. I was jazzed to see 2 40A breakers on the panel and purchased a NEMA 14-50 plug so I can charge at the max 32A that the included charger can charge at. When I went to wire it up, I realized that it was not the 4 wire arrangement that is needed for a NEMA 14-50 but the standard 3 wire (black, white, ground). I have 2 questions: Is it possible that this is a 220v or can that only be achieved with 4 wires? Second question: if it is only 110v what plug should I put in to allow for the fastest charging?