how much compression is still goon on pump gas?

Im in the process of builing my own little performanc engine, and Im buying these Gm performance pistons that will give me 9.8:1

is that still 87 octane useable?

Im in the process of builing my own little performanc engine, and Im buying these Gm performance pistons that will give me 9.8:1

is that still 87 octane useable?
Cast iron or aluminum heads and what design?

Cast iron or aluminum heads and what design?

Cast iron 58cc heads. idk the design, its the 2nd piston on this page http://www.gmgoodwrench.com/perfpartsjsp/partlist.jsp?cat=9390&section=ep

I dont have these parts yet, im planning out my engine, to see what it will need.

Cast iron 58cc heads. idk the design, its the 2nd piston on this page http://www.gmgoodwrench.com/perfpartsjsp/partlist.jsp?cat=9390&section=ep

I dont have these parts yet, im planning out my engine, to see what it will need.
Cast iron non vortec heads with that compression will require 93 octane, if the cam is somewhat agressive, the effective compression ratio at low speeds is reduced so lower octane may work ,but cast iron heads is the key here, premium, plan on it. Unless you live in a high altitude area.

Cast iron non vortec heads with that compression will require 93 octane, if the cam is somewhat agressive, the effective compression ratio at low speeds is reduced so lower octane may work ,but cast iron heads is the key here, premium, plan on it. Unless you live in a high altitude area.

if the heads were alumminum would it help? As for cam, I plan to have a mild one, nothing to fancy. probably idle to 5500 rpm.