Offy makes an "adapter intake" for 3 1bbl carbs. Even comes with progressive linkage, I think. I believe you have to mill off the top portion of the intake runner. You would need to pull the head to do this. Another possibility might be to find someone who is real good at welding cast iron, and have a couple of carb mounts added to the ends of the intake for tripower. Would still need to pull the head.
