I could see doing this swap if the automatic is dead, or dying, but otherwise I think that it will take years for the swap to pay for itself in fuel savings. To do it right, you need to buy a used M47, a new clutch kit, new clutch cable, a used pedal bracket from a stick shift car, and probably a few other things that I am forgetting right now. By the time you are done, you will probably have spent $1000 on parts and a couple weekends crawling around under, and in, the car, for a 2-3 mpg increase in fuel mileage at best.