As Johnny Carson would say "you are correct sir"

The car being a 440-6 did not come standard with a rally dash (ie tach)like the Hemicuda so we are under the assumption (Galen, Dennis Kohr and myself) that the dealer fired up the hood tach out of the hustle stuff catalog.
and you are indeed correct it is a Dixco HT/x however it is labeled as such not plymouth or mopar.
when we discovered the car the decision was made to keep it as a period correct piece, besides ya need a tach. (shift by sound is too danderoulsy expensive these days) It makes an already ultra rare mopar that much more intriguing.
And ...........it works awesome... get to keep my head up to see peoples faces when the dana barks the carpets