My thinking on this, FWIW, is to pie-cut the forward flange area before painting - rather than pull the driveshaft out of the trans any amount.
Unless of course the openings need to be stock size.
I've done that on a Duster - flange ended up pretty much flush with the forward area of the wheelhouse.
It took close examination by someone who knew the original dimensions to see the opening was modified.
I picked up a good 2" of tire diameter room.
I'm not opposed to pie cutting the the 1/4 to open up the wheelwell, but do not want to go as far as I did on the old 1/4 panels, as I want to reinstall the original wheeelwell moldings, and rocker panel moldings. I'm thinking the radial will not grow like the bias ply slicks, and it shouldn't be as much of a problem if it's tight. I want the wheelwell filled with tire.
