When you owned your SC, did it have any of the timing change issues that model was known for?
You mean ‘chain’? Nope.
oops, yeah, I meant chain. Please pardon the typo.
For a minute I thought, ‘Something gets loose and the timing changes?’ Then the penny dropped and the gum ball rolled out. 
You’re thinking of the 1974-1977 911, not the 911SC, made from 1978-1983. It was specifically overbuilt because of the issues with the mid-70s 911 models. The 1978-1989 cars are stupid reliable, especially after 1984 when they went to fuel injection and the airbox issue was eliminated. I’ve seen an SC with 500k miles on it - looked awful, was due for a rebuild, but it still ran.