[Hart_Rod]

You would only gain 12" to stretch the cab by doing it that way. My crew had 33" added in the middle of the front and rear cab mounts to achieve the 2 rear doors. I built my chassis by taking two chassis's (SWB rear section and LWB front section). Take a look at my crewcab build. There's some good discussions and lots of pictures that show how I put my chassis together. If you have any specific question, let me know.

R/