392 in a 70 Duster

Will you have room in your tunnel for the driveshaft adapter? It' hard to tell from pics but you may have to expand you driveshaft tunnel upward.
Just something to consider.
EDIT: I just looked at mine and yours looks about the same hight. I guess I did expand my tunnel a little... I just forgot that I did. Old age is catching up!!

It's pretty tight. I think it might need a bit of massaging. Did you go with a flanged driveshaft or did you convert yours to a slip-yoke?