68 GT convertible project

Today I grabbed one of the 20" wheels from my Durango out of the shed and put it under the Dart just to see what it would look like. The width is perfect. It's a 265-50 tire. There is about 5/8" on either side of the wheelwell. The tire is WAY too tall though. The tire is almost hitting wheelwell in the front and back. The backspacing is also way too much. At least it gives me an idea what 20's will look like back there.
DSCN2337_zps45a01d50.jpg

DSCN2338_zps19b4f70d.jpg