Originally Posted by Frankie
Exactly. My Harley is 8.5:1 compression, but with 34 degree advanced timing, I have to run 93 octane or it's ping city. On the other side of the coin, my 350 SBC is 8:1 compression and runs 12 degree advanced timing, so I can use 87 octane and still get decent performance.
Also, my Honda was 10.8:1 compression, and had relaxed enough timing to run 87 all day without a ping.