Carb tunning/mod question

Ignition timing, especially initial, first. That has to be right before messing with the carb.

What is the initial timing? If it's not at least 20-24 range, it doesn't have enough initial based on what I recall your build having in it.

Drilling butterflies should be a last resort to tune an engine as is used primarily on cars with not enough initial timing. Get the ignition sorted out. There are a bazillion threads on here about setting initial and total timing.