I had 4.10,s in my 73 D.S,took them out and put the 3.23,s back in.In my 66 Dart I had 3.91,s and swapped to a 4.30 spool(and taller tires)good thing,as the 3.91,s had a broken tooth.Crunch,crunch.Glad I caught it on time,before mulched into little pieces.
my Signet runs a 3:55 suregrip with a 727 trans which the first gear ratio is 2:45 and the tire height is 25" so in reality comes out of the hole nicely but I am considering running a T56 trans which has a first gear of 2:66 and 4th gear is 1 to 1 and both 5th ( .62 ) and 6th ( .50 ) are overdrives which should give better balance to all around street driving as well as coming out of the hole. Yet I may change the 3:55 to 2:76 and still come out of the hole like it has 3:55 because of the T56's first gear of 2:66
This is reality for today and something they wanted yesterday
4.56 suregrip posi in my 489 center 8 3/4 in my 72 duster
have not had a chance to really drive the car yet as it is still under construction but I don't drive on the highway really anyhow so it should be ok for cruising around town.