I've been toying with an idea for a while now but the biggest hurdle was the intake manifold - bike carbs. If I used the lower half of a 2.4 manifold and sculpted it down, then had some 36-40mm ID alloy tube welded into it, it might be viable to adapt a quad carb rack off something like a CBR900RR. They're big stonking carbs that will flow whatever you can squeeze out of them. The throats are 38mm which matches something like the 38DGES Weber carb but being side drafts would have serious throttle response.