Medium Duty SM/CH465 input shaft size?

[Campbel45]

Hi guys,

I'm looking to confirm some info. What are the input shaft sizes for the 67-72, C40-C60, ch465 trucks?

I have read that it could be either 1-3/8" or 1-1/2", and NOT the normal 1-1/8" size. I've yet to pull mine apart to measure.

Advance adapters say it is 1-3/8" https://www.advanceadapters.com/tech-vault/2-gm-sm465-/

If it matters, my truck is a 1968 C50

Thanks for the help!