ok, has being done many times. You can make it in severaql ways.
You can get ANY rallye cluster you want from 71 to 74 but several stuff you need to know first to get the propper parts matching your 72 ( or whatever year you have )
-----2 kinds of cluster available with 3 diff setups:
-basic rallye with big gauge double meter at a side of the speedo, then two small individual meters on small openings ( 1st setup )
-more equipped rallye cluster with dual double meters on small openings. The big opening at a side of the speedo can get clock ( 2nd setup ) or tach ( 3rd setup )
-gauges, housing and lenses mask between these last are the same, but not the first one. Just speedo interchanges between them
-same about housing
-Lense mask changes allong with housing as mentioned
-bezel "is the same" ALTHOUGH 74s got an extra icons at a side of the lights and wiper switch, for international understanding. Bezels interchanges though
-A clock cluster can become into a Tach cluster just changing the gauge easilly. need to add the tach harness though
-----speedos changes allong the years, although interchanges. 3 ones as far I know ( aside Kilometers ones )
-150 miles with vertical slot red high beams pilot light ( tipically 71/72, some 73s ). Red color made with a tape
-120 miles with horizontal slot red high beams pilot light ( tipically 73 ). red color I THINK with a lense
-120 miles with horizontal slot and blue beams pilot light ( tipically 74 ). Blue color with a lense
-----AC/Heater controls... 71/72 diff from 73/74, aside the diff options on cars... but you will keep your existant one from the standard cluster. Will fit on the Rallye one
----- wiper switches
-Rallye and Standard get a diff one. Rallye are a way shorter shaft
-71 is diff from 72/74. Prongs disposition and plugs are diff between these. So will need to get a cluster with the propper switch for your car ( considering 2 or 3 speeds ), or get the switch separatelly. IT CAN BE INTERCHANGED though, if you consider and match the plugs. I did in fact installed a 71 variable switch the cluster I got included ( only year option for these so kept this featuring for my car ) into my 74 getting the plastic plugs from a 71 Coronet donor, since wiring is the same, just plugs/prongs changes
-Knob is diff too between standard and rallye, so the most complete you find, the better. These knobs are hard to come by since they EASILLY get lost
-Nut is diff too ( once again, the most complete cluster you get, the better )
NOTE... the standard cluster switch shaft switch CAN BE cut to the Rallye cluster size... I have done it with success...
----Headlight switch
-Swith itself is the same, BUT same as above not the knob or the nut ( once again, the most complete cluster you get, the better ) This knob is hard to get lost so TIPICALLY on a cluster including switches, THIS KNOB is also included