[olddog]

Without using desktop dyno, my gut feel is you will give up 30-40 hp (verses 10:1). Depending on which AFR heads, I would guess at least 350 Hp.

I expect you could run 87 octane gasoline. You could always add a blower later if you want more power.

PS:
I'm no builder. Just read a few books. Well I did build a few Chevy and a Mopar 35+ years ago.