I stopped by a Firestone dealer today....
They have to order the Indy Firehawk 500 in...but gave me a great price if I go that route......$490 or so installed, etc.
Thats for two 275 60 15 tires and two 235 60 15....
One thing they couldnt do was give me the tire heights.....
I have 15x8, 4.5" backspacing (0 offset) wheels on the back and 15x7 4.0 " backspace (0 offfset)
From what i can see reading other threads they should fit.
The firestone guy says that if there is an issue when he mounts them he will take them back.....
Still not sure i want to go all the way to 275 rear and 235 front.......