Pics? Is it an oppy or a v-twin? (I'm assuming it's an oppy)
Typically on a 2 cylinder, a dual barrel carb is the best. I have also seen manifolds that bolt right to the block, one on each cylinder, and have a Mikuni or some large single cylinder carb on each cylinder, and linkage running between the two, but it is very expensive and complicated to do that and have both synchronized. What HP is it? The higher hp ones typically have dual barrel carbs, at least that's the way they are on v-twins.