Well for one thing, they are designed and set to run as lean as possible without burning themselves up. If/when you take off the air filter and/or add some sort of a free breathing exhaust, they are going to lean out, perhaps (probably?) more than the stock carb can be richened up to compensate. Since one is basically stuck with the carb, if that is the case all one could do is try to modify the carb internally to allow it to flow more fuel. The other alternative is to block off the secondary intake port, and run a "normal" carb. I really don't know how this would affect overall power with the SC design.

I think someone here in the forum did just that with a Poulan however. You might search for that thread for more info.

AV8TOR