You'll be fine on pump-gas. You can likely even run 87 on it if you want to. I'm running a 454 at 400HP with large oval port heads flat tops, and 123cc chambers. That runs me just a hair under 8.5:1 .You don't really need to get over 90 IMHO untill you get a bit over 9:1 and liklely could get close to 10:1 on 93 octane. I usually run premium to go with my Nitrous usage, as a backup for detonation protection.
10 degrees initial timing is fine, 35 to 36 is good total, right where it belongs. I'm currently running 8 initial breaking in my rebuild and she does run strong! Will goose her to 10 to 12 or so in a few weeks. See what she'll take without problems.
Incedentally, here's a link to data qued to your casting numbers if you care to look at the back of the block above the bellhousinbg and under your valve-covers:
http://www.mortec.com/bbc.htm