Another 489bbc question

[Roll'nSlo]

Ok, so E85 runs better at CR of 12+?? I don't mind going higher in CR, just don't want to use racing fuel.
I was going to use a th350 cuz that's what I have on hand. I'll see if I can get a 400 reasonable to rebuild. 3.73 I can do, I was going to go with 4.11 just to help it.
On the heads, I really want to use the 781's. If I need to go to larger valves I can. It'll be easier to rework them. I can buy the valves and hardware as I can afford them.