with a small bore like 3-3.5 inches you may need about 95-100 pump octane # to run 1.5 atmospheres or more like that. usually 10 to 1 or higher is only used with methanol when superchargeing. for pump gas at 10 psi you likely want about 8 to one. intercooling, combustion chamber design, engine speed etc will all determine what you can do. at 10/1 you will likely have trouble at only a few pounds of pressure even if its cool outside. with premium gas you may get away with a few psi or more but its pretty iffy. also if you want to run 10 psi you best look at piston expansion VS clearance. unless the engine is worn a bit you may want looser clearence or better yet pistons with more silicon( like hypereutetics) id get a set of pistons made for it or not bother. unless you were going to run methanol or water injection.
edit: also i should say beware hypereutetic pistons with no knock sensor on the engine. these pistons are easily busted with detonation. detonation aside though consider this general comparison; 2 engines one 6/1 with a superchager at about 4-5 psi and one 10/1. the 6/1 engine will make about the same power as the 10/1 engine but will have maybe 70 % less physical stress on the bottom end. the trade off is lower ratios waste more heat that must be dissipated. pressure or heat, pick your poison.
