hi,

as with many original parts there was a margin of acceptance, so understand there isnt going to be 1 correct answer

here is what i have found in original cars:
(t-type if not noted tube)

67-9 Cuda Jack Mast Length 33-1/2”
68-70 Charger Jack Mast Length 36” (2 CHECKED OUT AT 36”)
Superbird 34-3/4”
70 Challenger 34-5/8”
70 Cuda Tube 35”
66 Satellite Tube 34-1/2”

i hope to have my new t-type jack assemblies available by winter