I'm for some reason unable to post a picture from my computer, so for now my avatar will have to do for pictures. Here's the products I used:
Cragar 342-5712P Cragar 342 Series Black ''D'' Window Steel Wheel
BF Goodrich 67244 BFGoodrich Radial T/A Tires
Due to the stock car-style black steel rims usually being rwd offset, the Cragar 342 wheels I found were pretty much my only option for this particular look. And even they are low, only +24.5 mm. As Bio248 mentioned, the rear fenders had to be rolled on my '01 GT to clear the tire.
As for tires, since I had to go down to a 15" wheel, I went with BF Goodrich Radial T/A 225/70R15's. They are pretty darn close in diameter to the stock 225/60R16's, while still giving the fat rwl racing tire look.
BF Goodrich is apparently having production issues, so some of their sizes of the Radial T/A are scarce at the moment. You could also go with these:
Mickey Thompson 6025 Mickey Thompson Sportsman S/T Radial Tires