Bruce,
right were the flange for the the output shaft/gv meets, it fits, but could use a lil clearance. It isn't much but to keep the best driveline angles it needs to move up 1/4-1/2 an inch.
I hit it with a hammer a few times and jacked up the sheet metal a lil there.
I believe it's under the back seat, so appearance isn't a huge deal. I'd just put down carpet, but would have liked to have really made the area much higher.
I did the math on AOD capable of surviving 600hp and slicks vs a c6 +GV.
I did NOT buy my GV at retail, I took a salvage unit and rebuilt it.
Even at retail The C6/GV won out.....
Your math might look differently, but when you figure all the work to get an AOD to survive, plus that fact that I used nothing but stock parts in my c6, plus convertor cost, etc, the c6 makes more and more sense.
There is no part for my setup that I can't just order out of a catalog.
My math also counts me building everything, so there is that.
Either way, looking back, I wouldn't do anything differently.
If you do a 63.5 Galaxie with c6/gv the driveshaft will end up in the 45.25-45.5 inch range. I used a 4inch aluminum, no complaints.