switching from 68 to 73 will it work

One more time , these 3 pieces must be a matched set, center link, pitman arm, idler arm. Easiest way to sort this out is measure the hex nut on the steering gear. That shaft size determines the nut size ( 2 different ones ). From that determine the pitman arm you'll use. from that you determine the matching center link and idler arm.
here's a tip... most tool boxes don't contain a 1&5/16 socket. If that's the socket you need, you have the larger of the 2 sector shafts.