'73 Dart Sport 340 H Code leaf spring replacement recommendation

I have a dart sport with cheap dynomax coated headers. Also had 14 rallys. Drivers header always was hitting @ driveway, manholes. So went to 15x6 front & 15x8 rear rallys rear. Front tire 215/65/15 rear tire 275/60/15. My rear leafs were arcked down!! So bought some new mopar performance springs. All good now!!