I just bought some new KMC 8 speed chain for my five speed freewheeled touring bike, but it's about 5 links too short. I've got some Taya 6 speed chain sitting that I could add to make up the length. Can I combine the two, or do I need to run all the same chain?

You can certainly give it a try, use 2 quick links ..

Past 8 speed the chain gets thinner
5 to 8 is sold as using the same 3/32" chain.

I know many will say no.. but probably it will work just fine. 8 to 10 speed chain i wouldn't do it but from 8 to 6 is basically the same chain or really really close. Give it a try.

Haven't done it with those particular chains, but I've done the process before it works about 50% of the time for me, really just depends on the pin length to chain link width sizes...

Thanks! I'm glad I didn't end up having to buy another chain just to get this to work.

I just did it, and while the KMC links have "Narrow" printed on them, both the links and the pins ended up being the exact same length and they seem to have the same amount of flex. If they were the same color, you wouldn't be able to tell the difference.

Side note: Taya is generally the brand used for private label chain (i.e. Bell,) so if you find yourself in the middle of nowhere needing links, this will work.