Got around to swapping the rear Bilstein shocks into my 69 GTX. The upper sleeve for the Bilsteins was shorter than the KYB so I put the KYB sleeve in the Bilstein upper bushing. Very easy swap. I measured the travel of both for comparison.
KYB. 22 5/8" to 14 1/2"
Bilstein. 22 3/4" to 14"
KYB. 22 5/8" to 14 1/2"
Bilstein. 22 3/4" to 14"