I did 6.5s up front and 7's out back. 5.5s seems to small for me but I'm also using a standard front axle so I don't worry about turning. Seemed to fill out the rear wheel well. I have a 2" drop axle with a shortened track width (for wheel to fender clearance) from another project, but haven't wanted to install.
5.5 white walls are only in 1-2" (back when I ordered). If you are going 3-4" WWs. Better if they match.
All the pictures are not there anymore but...
https://www.fordbarn.com/forum/showthread.php?t=42056
6s and 6.5s in the rear.
6s & 7s
A set of 7s out back would be nice on your car.