How big are the valves, what does the chamber look like, drawing of the port X-section?

I'll repeat what was considered good info 50 years ago:
2 carbs are a big help, better mixture distribution than stock + more power and almost no loss of response (if carb size is small).
3 carbs only add a small amount of power and only with a cam and exhaust change, reduce response, and may have worse distribution than stock using progressive linkage. Straight linkage cures the dist. problem, but makes response and mileage very sensitive.
If you're comparing manifolds by appearance you're making a mistake.
You could run 3 × 1 bbl. side draft like the Corvette if you have room.