I have not owned a /6 before (worked on plenty, though) – nor have I personally measured any throttle cables for length.
All I did was make note of what I found on the internet and in a Pioneer throttle cable catalog - for my own reference (Big block, 6-pack and for fuel injection possibilities).
I do know that a /6 1-bbl and 2-bbl cables are different length – so a cable will be needed in a 2-bbl (Super 6) changeover (is not even close to being long enough to fit).
I’ve heard stories of other forum members using a /6 1-bbl throttle cable when replacing with a V8 engine changeover – without troubles – but I suspect a /6 2-bbl cable might be too long to work with a V8.
BudW