For your combination of compression, engine displacement, elevation, and gearing you have too much camshaft intake duration.

Try swapping in a Summit K2800. The split pattern will help the exhaust side while promoting cylinder filling to where it is needed.

The earlier heads on the 67 tend to like more total timing. With that compression ratio and head design you probably should run about 91 octane, but max mechanical timing can be 40-42°with the correct octane. Borrow a dial-back light, because adjusting the max without knowing what it is, is Russian Roulette. Ignition timing curve will be dependent on the camshaft and with the 2800 I'd start with around 14° and see what it likes (have it all in by 3000rpm). Since the HEI max advance is not really adjustable you'll need to elongate or shorten the advance slots by grinding/brazing to adjust the total. Remember the shorter mechincal range will mean higher spring rates to slow the rate otherwise you'll reach max advance too quickly.

Once you have mechanical set (keep the vacuum advance disconnected up until now) get an adjustable vacuum can (Crane makes the best since you can adust teh spring load and the total) and adjust it per their recommendations.

Once you have these dialed in correctly you can fine tune the carb.

One more note, because you've switched to an HEI, you may want to try opening the spark plug gap up to .045". Maybe try this before you do teh other stuff and see if it likes it.