I've not done this swap on a 69 Charger, but I have played with enough Mopars of this era to know Chrysler quality control, as far as body tolerance are concerned, was pretty loose.

I suspect what actually will need to be done will be car specific. You can line up 10 different 69 chargers (or any other Mopar car line) side by side, and the modifications required to perform the same task will probably be different between more then 1/2 of them. The differences can range between very easy and very difficult, or be anywhere in between.

Posted in this thread may be both extreams, Moperx won't know what will actually needs to be done until he gets started. Gene