You'll need to be aware that some carburetors simply can't be made to run rich enough to work in a multi-carb situation. Fuel/air mixture is mostly controlled by the volume of air passing through the venturis, and if they're too large the velocity will be too slow to create enough vacuum to draw fuel into the airstream, no matter how big you make the jets. Putting two (or more) of the same carbs that work right in a single application is a recipe for disaster. You MUST use carbs designed for an engine about half the size of the one you're running for a dual carb setup, and even smaller for triples.
Jerry
