225-50-16 would be almost 2 inches smaller in diameter than stock tires, and no wider, and would probably look very silly in the big T-Bird fender openings. No worries running 245-50-16 or even 255-50-16 (that's the size I'd recommend since you're going with 8" wheels) ... even on a lowered car. Lots of people are running those sizes with no problems.
cheers
Ed Nicholson
SCCoO