That 270* cam might be too much for the low compression engine. You might be able to hide it by advancing the cam timing by a degree or two.

I would run more ignition advance, what you want to see is around 36* TOTAL advance at the engines peak power RPM. Thats base and centrifugal combined. The vacuum advance is really a band-aid to help during acceleration, so it doesn't affect PEAK, but will change performance.

Make sure your advance can is hooked to ported vacuum. On the Edelbrock carb, it's a small horizontal line on the front of the carb facing the front of the engine.

Good luck, it sounds like it could be a wicked-fast ride when it's tuned right!