What should 273 compression be

I'm having problems with my car back firing so I finally decided to pull all the plugs and check cylinder presure all the plugs looked dead rich except for one
I kept thinking I had a distributer problem that's why it was back firing

my question is do any of you know what my stock cyliner presure should be for a 273 cid my reading ranged from 110-118 was wondering if it needed new rings, haven't checked leak down yet