Sorry for the Mistake in the Header of the post. Engine is 2hp. With the up grade top end, you can make it 3-4 hp. As for loudness, it is louder than the stock F series motors, but not so loud it will offend the neighbors. But.. it is not stealthy quiet like the Titan 4 strokes... Forgive me for not being able to post so much in the room as Duty calls on a constant basis. But remember, you can always give me a call or email me directly. Thanks.. Enjoy the ride..