I have a 67 Travco with 6 lug 16 inch rims. I am trying to find something else to replace these with. By the way, they are split ring, which no one will touch any longer. I am coming up empty with any replacments, it seems the 6 lug was used only a year or two so the options are slim. How much work is it to change out the rear axle and front hubs to 5 lug?