Towing kit advice help

I have a 74 sedan with the tow package it has coil over shocks in the rear and the hitch has 4 bolt, two to the rear bumper and two to the trunk pan into 3x3 plates welded into the tire depression, if it helps I have towed a 4x8 open trailer with two large bails of hay that maxed it out but it still towed it.