Help me diagnose my miss over 4500rpm.

Sounds like classic fuel starvation to me. No way in hell are you ever going to have spark knock problems with 100 PSI cranking pressure. You could probably run off 79 octane. Tape a fuel gauge to the windshield and tee it into the fuel line at the carburetor and drive it down the road. I bet the bottom drops out of the fuel pressure. Unless you actually diagnose it, you may never find out what's wrong. The fuel gauge taped to the windshield will at least confirm or or eliminate a fuel problem and is very simple to do.