Virgin sheet metal is a lot easier to work on than rusted stuff is I would (and did) stretch the wheel wells now before you finish the car and paint it. My car has the wheel wells stretched five inches, three inches forward of the original axle centerline and two inches to the rear, I also moved the rear end forward one inch at the same time My car in this picture has 315x60x15 MT ET Street Radails on ten inch rims with 5 3/8 backspacing (it was suppose to be 5.5 backspacing )I also have a set of 10.5x31x15W tires on ten inch rims with the 5.5 backspacing and they fit as well as the M/T radials do and the slicks fill the rear wheelwells up a little better I use ladder bars and coil overs and full size wheel tubs into the stock sub frames EDIT: Oops, forgot to attach the picture Last thing, several years ago I was at Mopar race at Woodburn drag strip here in Oregon, a younger racer came up and stoop down to look at my tires and car, he stood up and said "you can't fit those tires on these cars, I have a 1971 Duster and there is now way I can fit that size tire on my car I let him look at it for a while and finally told him my 1/4 panels are not stock, he gave me a weird look and stoop down again and took another, closer look I fool him and a lot of other Mopar racers and street people Do it now,(sheet metal work) not later