[DeTomaso] Odd Size Nut On Damper Installation Tool?

[Ken Green]

I bought a damper install / puller and would like to use a box end wrench to turn the nut to pull the damper onto the crank.  I measured the nut with a dial caliper, and the lands are 1.275 (within a couple thousandths) on all 3 measurements which doesn't match any normal fraction (is 1 and 11/40) and is about 32.385 mm.
   
  Based on this I'm assuming the nut is a custom part that doesn't match any standard or metric wrench, but before I give up and use a crescent wrench, can someone confirm that kits like this have odd ball nuts in them?
   
  thanks