Another 2wd to 4wd ??

[6600DURAMAX]

I know this has been asked a hundred times but I cannot seem to find the old threads. Ae the 2wd and 4 we'd frame rails the same. I am looking for a 4wd Shortbed frame but have the ability to convert a 2 we'd if the frame rails are the same. What about the rear of a 2wd leaf sorting truck. Are they the same hangers used on a 4wd frame?

Are the body mounts positioned the same as far as height goes?

I am not worried about the cross members as I am going the LS route and will have to fab stuff anyway

Thanks guys