dude, you'd do yourself a disservice putting anything other than a bastard on that engine. you've already gone through all the effort of getting the right port and everything, why not go all the way and run the highest output pipe on it?
also, i don't think that running the stock carb would overheat your engine, just wouldn't get all the power out of it. so i'm pretty sure you'll be just fine running hte stock carb on it, you just won't feel the full power of the engine.
make damn sure you jet it right though.