I'm out of ideas. My SBC starts to miss once it top 4800 rpms. The fuel is fine, I've confirmed that on the Brian's dyno. I have check and replaced everything in the ignition system: coil, HEI module, plugs, plug wires, distributor. I've played around with the initial timing and the timing in the computer. The miss has gotten better, but it's still there. Does anyone have any useful suggestions? Thanks.