I think Goose pretty much hit it correctly, but I was also going to add that the front end looks to sit a little low for stock. Goose brought up a good point about your springs being correct for that engine, but I was going to ask if those are stock springs that have been in the car for ages and they may in fact be tired and need to be replaced all together, even if they were for the 455. I actually dont even know if the springs were different based on the 350, 400 or 455. Typically with good front end springs these cars had a nose up attitude were your looks to be down so that leads be to believe that the front springs are tired and worn or the incorrect springs or the suspension up front isnt stock and has a drop from the springs or something else. Worth looking into which might set you straight. I have heard from and read plenty of folks say that those tires sizes should fit fine with a good suspension.