'65 temperature sender unit - top thread size?

Howdy folks. New here. Just need a bit of help. Does anyone know the thread size of the top bolt of the temperature sender unit? I'm rewiring my 65 and the original spark plug shaped boot is broken, so I need a nut to hold down the new connector.

I think, it's a 1/8" diameter and possibly 32tpi, making it UNC. But I'm happily corrected if I am wrong.
 
  • Sponsors (?)