What should be a normal compression ratio for 90. 300SL (automatic) with 3.0L engine?

Compression ratio is a design feature. ON that engine the compression ratio was 10/1.

Do you mean compression pressure with a gauge while cranking starter??

That should be 12-15 bar, with a difference of less than 1.5 between cylinders.

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Sorry !

I was thinking about one thing and writing about something else.
Well , compression pressure on my car is 120 - 125 PSI.
Based on what you telling me 12 - 15 bar (175 - 220 PSI) this engine has
low compression.
My problem is that when I try to speed up fast , it takes too long with
hesitation (almost like missfire) and engine stalls sometimes when I'm slowing down to stop (not all the time!).
On the highway this car is cruising with no problem, but city driving is different story.

Complete tune up has been performed - dis. cap & rotor
air & fuel filters
fuel pumps
spark plugs & wires..........

I performed scan test with AUTOLAND scanner and code 16 is showing.
Another scan while engine is running tells me No Codes!
I dont know can I trust this results?
No vacuum leaks or bad conections.

I dont have idea what to do next, all this drive me crazy.

I reasly appreciate any help or suggestion.