8.8 swap

so i found this post not to long ago. i have read through it but may have missed somethings. let me start here. i have a 65 dart. it has a 8 3/4 in it now. been wanting to update it to discs, bbp, posi. i have been doing some thinking and i fill this is a better route in the long run and cheaper then my 8 3/4. how long is the 8.8 housing once you cut the drivers side or maybe someone knows how much wided is it the a A body 8 3/4... and last is this a dumb idea?