You are definitely limited on wheels. The tried and true combo for the dart body with a stock rear end/leaf location is 15x7 with 4.25” BS coupled with a 255/60r15.
Is this combo and 4.25 backspacing for an A-body with the 8 3/4 rear or 8 1/4 rear? They say the width was different between the 2 rearends, thats why i ask. Im about to order the wheels so need to be sure. thanks!!