I like this chain, it's very durable and will go over 150,000 miles...
https://www.manciniracing.com/ed2733183403.html
Then do a compression check dry and wet to see if the rings are in good shape... Chances are they are ok, the original timing chains for the 318 stretch easy... I replaced one on a 68 318 with 84,000 miles and gained 2 mpg...
