SS Hemi Dart dimensions...

Hey y'all, I'm new to this forum, but not new to mopars! I figured this would be the perfect site to aid in my 75 dart project...I'm looking to make a budget street/strip car and need some help fitting bigger tires. It's got a B-body 8 3/4 rear (stock width) and since the body has seen many a better days, I figured the cheapest/easiest way to fit big tires on the rear was to cut out the rear wheel openings like the 68 ss darts that came from Hurst. Anyone know the dimensions of the cuts or the specifics? Any help would be and is greatly appreciated!

Thanks in advance,

Joe.