help- tire's are rubbing

hello guy's, i need some help--i have owned 2 67 camaro's and both would bottom out and rub the tire's--i never had this problem on my 68 or 69 camaro. i have a 10 bolt rear end in the 67 camaro--the car does great with only me in it, but if i take the family out in it, it sound's like the...