I run @ 11.4 with ede alu heads , 94 octane , with 91 it will ping unless I play with the timing , can't imagine running 87 octane . Runs best on a mix of 1 gal118 octane / 3 94 octane .
I would guess that you are a little closer to sealevel there and are benefiting from the denser air.
I bought a dash-mounted dial-back timing computer. It helped me zero in on the perfect timing curves for the various iterations that my little 367 has gone through.But yeah the timing curves(mine has a kink in it at about 2800) were time-consuming to say the least.
But in the end it was worth it for several reasons; 1) the engine is real snappy when it's right, and 2) running 87 for 120,000 miles has saved me a lot of cash, and 3) I get to preach the 87E10 on 10.7 to 11.2 story. On either iteration, I've been running a Dcr of 8.6 to 8.8, or a bit better.
That comes to about 40,000 liters. Let's see, what's the $ difference from 87 to 94 plus some 110. I dunno, but I guess I saved between 3 and 4 Gs by now.
Your results may vary.