63/64 Darts have different front wheel wells than Valiants/Baracudas and 205/60R15 is the biggest that will fit on front. Unless you trim the bottom inside edge of the front fenders.
805 is about spot on. As far as tires, Lee (lilcuda) is running 215-60-15 Yokohamas on all four corners. That is in stock wheel wells. You have to ask Lee if there is more room or how those tires perform.
