The integral heads are OK as long there is no heat cracks or exhaust leaks. With the two barrel, they actually run decent. The problem with swapping carburetors that require adaptors, is the adaptor itself is a strong choke point. Even if the carb going on is a good one, the adaptor will likely kill the benefits of the better unit. If you get shape it right and minimize the miss match, you might get away with an adaptor, but the best bet is a better stock carb than you have, then it will bolt on and be calibrate for the engine.
