Widest Tire/Wheel combo for a '72 Duster?

This is what I have on mine. 245/45ZR/17 Toyo Proxes FZ4 on American Racing Hopster 17 x 7.
Hope this helps?!

http://www.americanracing.com/browse_vintage.asp

Part # 550-7765 Size 17-7Offset 0 Backside 4 bolt circle 5- 4 1/2