I have 10.9:1 cr now, with alum. heads and a large duration cam and runs fine on 93 pump gas. I hit 6500 rpms often w/o any pinging, with a large cam the valve overlap helps bleed off the compression, but your right 10:1 does make a better street motor but you can run 11:1 run the street w/o race fuel.
11:1 can be done and be streetable but when you start getting around the 12:1 range you will run into trouble in a street motor with out racing fuel or octane booster. With cast iron heads I would not run over 10:1, there is no way you could run 12:1-14:1cr without major problems, also on the dyno the hp per one cr point is not that great, certainly not worth the headache.
Just my opinion
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