Rocky's statement is correct. The conversion is not that difficult. There've been posts here and elsewhere on the conversion, on a number of different cars. Here's one for my car for example.
board.moparts.org/ubbthreads/ubbthreads.php/topics/1347457/2.html
It's hard to make out in the photos but you need to open up the sill on the four door rocker or swap in a two door version. I have seen people weld right to the sill but if you do that the water has nowhere to go and you'll eventually have problems.
