Compression...

There should be absolutely no reason to ever need 110 octane fuel for a 9.5 to 1 compression if the timing is set right. Racing fuel burns slower and with the lower compression won't benefit you anything. I've read reports of it actually losing HP in a low compression engine.

Streetable compression has a lot of variables. The cam has alot to do with how an engine acts. A larger cam will bleed off some cylinder pressure and allow a higher compression with the same fuel. This is where the difference in dynamic and static compression shows up. Dynamic compression is what is really important.

Head material also comes into play. Aluminum heads disapate heat faster so you can run more compression with them. From everything I've read about .75-1 point higher for aluminum over iron heads.

All in all with iron heads 10-1 is a good figure to shoot for with todays junk gas with iron heads and a fair size performance cam but I've seen many guys go over that with a proper setup and still run pump gas.