quick CR estimate on KB107's
I had my 360 block machined to put the KB107's at zero deck. I am running magnum heads that cc'd at 64. With an 0.039 gasket that works out to 10.6:1 compression. I have a cam with less duration 268/280 which will give you more cylinder pressure than your 292/292 cam. I have 185-195 psi of cranking pressure. My engine runs on 89 octane and I can run 87 in a pinch if I take it easy.
If you don't deck your block block you can figure the compression will be under 10:1. With closed chamber aluminum heads and your cam you could easily run 11:1 on 91.