Tire Size

I need some help.

I have a 68 Dart - no body change - with a 1975 8 1/4 A body rear and 1973 disk brakes on the front -

Rim size is 15" standard mopar steel wheels

What I would like to know is, what is the tallest and widest rear tire i can run without it rubbing on the body or the rear springs?

Secondly, what is the widest front tire I can run without them rubbing on the frame? I want tall, but I am really interested in is how wide?

I want both front and rear tires to be as wide as they can be!

Please give me what you think in metric measurements, please

Thanks, Sam