I looked at one yesterday. 49.5 inches center of u joint to center of u joint.
The owner was about 90 percent sure that it was from a 1969 Camaro TH400
car that he junked out after it was wrecked about 30 years ago.
It had what appeared to be an original TH400 yoke on it. The u joints were in line.
I could not find any stripes on it.