Can a 400BBM w/cheap aluminum heads compete/dominate against the street LS?

I never ran E-85 in my cars but have been thinking about it. But in our area it is very inconsistent. I've been looking at it on my tech2 on my x suburban and I've seen it from 50% to 90%. I haven't priced it in a can yet.
Yeah E-85 with maybe some AVgas would be great, and affordable, but like you said inconsistent (we found it to be very dirty (perhaps less refined or filtered) in South East Georgia.
But 108 octane would cushion against detonation on a high end build.
I wonder if it would separate if mixed with AVgas while sitting-needing a binding agent?