8" sounds really wide to me. You could use a calculator online to see how much room it will take up inside and out.
And some tires (although the same size) are wider and will rub while others won't.
Hi. I run 7.5x17 ET35 with 225/35R17 tires. And this is around 10mm to the damper for the rim at the front. With 0.5 inch wider and ET40 this is 11.4mm closer so I think this won´t work, or is f###### close...