You still need to look at the dynamic to say for sure
but on my 416 with 9.2 dynamic and iron heads I can
and do run on 87 on the street..I get ZERO knock..
if I want to run on the track I will add some 93...
you can add more with alum heads




Just spoke with my engine builder, he recommends stay near or under 8.5 dynamic for 91 octane. That means I'd be going with 80cc stealth heads, 440 source 512 stroker with -27cc pistons. Gives me a compression of 10:1 and dynamic of 8.4:1. What do you guys think?