Widest front tires

Depends on several factors. To get a larger choice of wheel, many have converted over to the 73+ disc brakes. This pushes the wheel out from the original location about 1/2 inch per side. Because of this, the backspacing is critical for the correct fit.

I do know of people getting away with 245/45/17 up front with wheels with 5.5 inch backspacing. Of course this again is with the 73+ disc brakes. See michael mosely's experience with the set he was able to borrow.
http://home.roadrunner.com/~michael_mosley/tech/wheels.html

Here is another with 17" wheels and this time 235/45/17 wheels. http://www.mooresmopars.com/ModInterior.html

I have done the conversion and run standard size 15x7 Cragars with 225/60/15, but I had to do some trimming on the edge before I took it to paint so they would clear. I only took out a pie shape just enough for them to fit.

Hope this helps.