I made the first intake just before Christmas last year. I needed it for the bike shown below.
The engine was mounted fairly level, so the orginal intake would have positioned the carb, angled down.
Your engine does not have to be perfectly level in order to use the intake I make. It's usually fairly easy to level out the engine a little so that the carb isn't angled way up.
The "O"-ring seals the connection between the carb and intake, which makes for a good idle...no more vacuum leaks.
The short, straight through, design is far superior for obvious reasons.