I'm new and dumb but have to ask. In my '65 GT I am changing from the 7 1/4 to an A body 8 3/4 with a 489 third member. In the '65 Dart/Coronet tech. service manual it shows on pages 3-2 and 3-3 the two axles in full assembly drawings and I noticed the lighter 7 1/4 case doesn't have a support...