Need a plan - component selection for restoring 68 340 that runs on 91 oct

Hi there
I'm new, but I have a 1969 gts 340 auto.
I put together my 340 last year also to run on 91.
It's taken a lot of trial an error to finally make it happy!
My combo:
72 .030 over. Stock deck height. Block
69 forged crank
Scat I beams
JE / SRP forged flat tops .010 below
Calculated static right at 9.5
Dynamic 7.5
JE plasma file fit rings
69 X heads no port work but hardened exh.seats. and guides cut for P/C seals and .500 + lift.
66 CC chambers
Fel pro .039 gaskets
Comp. XE 268h 224 / 230. @ 50
477 / 480 lift.
Installed 2* adv
Eddie air gap
Holley 670 sa (box stock)
Firecore vac. Adv. Dist.
Timing 18* initial
32* total mechanical
8* vac adv.
Mech. Adv all in @ 2400
Orange mopar ICU
340 hp.exh. Manifolds
2.5 tubing out the back
Dynomax ultra flo' s
I've tried about every spark plug for it.
It runs best with autolite 65's
I live in Phx. Az.
I drive my car every day and all summer at 110 to 115 *
It will not detonate on 91 with this set up.
But it is very sensitive to plugs and timing.
34* it will detonate, 32* is max
The rest of my drive train
998 with lower 1st an 2nd gear, with custom Hughes non lockup 2000
Stall converter
8.75 rear 3.23 clutch type sure grip.
This is a daily driver I take on the freeway too so it's pretty good all around.
Gets 16 mpg ave.
Would be more fun with lower gears though...lol

Good luck on your project!!