I have heard of people doing the conversion for as little as $1000, and up to $10,000. It all depends on what kind of deal you find on parts, how much work/fab you do yourself, and what kind of condition the parts are in (if the engine needs fixed, rebuilt, etc.), and how many other mods you do along with the conversion. I would guess a good ballpark figure would be $3-$4000 average for the total conversion.