Speedometer cable length?

I didn't keep the receipt, but the base price was about $19. The NAPA here shows two different cables on their website; a single cable of 68" and a two part cable of (I think) 80", which must be for later models. I got the single 68incher and it fit nicely. I'm mostly a B body guy, so I can't say this will fit all A bodies well, but it fit my '73 just fine.