383 to 727 help - 66 Charger

Ok let me clear the air by stating this isn't my car. My friend just picked up a pretty raw 66 charger project that someone did everything to about 80% and moved on to something else. The biggest and first thing is connecting the TF727 to the 383, so we can get it running.
This appears to have once been a 318 car with a TF727 (My buddy ran the numbers and this is what he says, I don't know for sure). The last owner swapped in a 383 and the flex plate holes do not line up to the flywheel holes to mate the two.
So my question is, does my friend need a flex plate or a flywheel?
I am guessing a flywheel because the flex plate would be specific to the 383 while the 727 flywheel is currently for the old 318 small block and it will need swapped out to mate to the big block set up.

Anyone agree or disagree?