Compression...

Good morning;

At the risk of repeating some and ...well, it's to early for me to read Mopers reply. Though I'll tell anyone else that hasn't, go back.

At that ratio, and octane, I agree, theres nearly no reason to ever use anything but pump gas. His balancer must be off and/or the wrong cam is in there.

Look at DGC's combo. High comprsion ratio and pump gas. Great squeeze and head design.

Streetable compresion is something everyone can agree on @ no more than what the local pump offers. Race gas exempt. Or above whats easy to get. In New York it's 93.
And thats key for me. Your max octane is key for you.

Thats why in general, I answer the question with not more than 9.5-1.
For anybody thinking thats not enuff of a ratio to get a engine up in some serious power numbers, you'll need to do some homework. Heres your hint to set you in the right direction to start your research.
Crafstman truck series. Engines are limited to 9.0-1.

Poor chamber design or just simply open chamber design and pistons that are very low in the hole will cause problems.