The efforts to protect people from their own level stupidity is getting ridiculous. Like any medicine ad today- don’t take this medicine if you’re allergic to it. Really? Do we really need to say that?
I believe you may be right but I’m not putting disclaimers after my posts- no mufflers were hurt in the making of this post… 
Yes, we do, or at least manufacturers need to so that they can avoid law suits. As I understand it, manufacturers are considered experts in court and should provide warnings for just about anything that might go wrong. The classic case is extension ladders. I’m sure you know all that.
I know why the company does it. That wasn’t the point. Should they really have to? Goes to the level of ignorance and stupidity we allow to affect everyone. At some point it has to stop being a money grab for how foolish a thing you can do and claim ignorance or no personal responsibility. If they were to list EVERY conceivable stupid thing you could do, the list would be endless. They decided to stop listing after allergies. Why not state- don’t take this pill through your ear canal? Just because no one has sued for that yet? Opps, somebody might believe that’s ok… 
Yup; I upgraded exhaust system in an El Camino big block 72 SS. Went to header flange size back through the mufflers (3") with an H crossover-there wasn’t room for the X crossover. I have had X and H crossovers in various other muscle cars and the X flows a little better and sounds different. The H works the best at the 18" header extension area. The upgrade made the Elky more frisky, but haven’t done the chassis dyno to quantify the difference yet.
Yes indeed! Love the sound of the old faithful R3350 turbo-compounded engines we had on our old EC-121K’s!
Two cylinder John Deere tractors had a 180 degree crank, piston going up while the other was going down. Good for balance but bad for even firing interval. 180-540 firing interval.
The Brit bikes with their 360 degree cranks, both pistons going up and down together, were
bad for balance but good for even firing intervals, every 360 degrees of the crank.
Japanese twins have used both 180 and 360 degree cranks. My old Honda 175 had a 360 degree crank, so did the Kawasaki 400 twin I had. Honda 350’s and my current Ninja 300 have 180 degree cranks. These two designs have a totally different exhaust sound.
Growing in popularity is the 270 degree crank, one piston is mid-stroke while the other is TDC or BDC. This gives a 90 degree V-twin firing interval and also the second harmonic vibration of the two pistons are out of phase with each other and cancel. The primary imbalance being countered by counter rotating balance shafts making for a really smooth engine.
Back in the early 1900s Ford I think it was had a single cylinder engine with a 300 pound flywheel. The engine red lined at 90 RPM. I can only imagine the sound and torque of that thing.
Sounds like the classic hit & miss engine. Lots of companies made those.https://www.youtube.com/watch?v=Rtv9QsXqll8