It is just a misconception, and it comes from people who are not very mechanical and can't figure out why the speedo says 80 or 90 yet they can only cruise at 50. That is probably one of the main reasons. Get enough people that say you have to change to a full pressure engine and the next thing you know I have numerous spare 216's that I got for free or for next to nothing in the barn
so maybe you should change and just drop that engine off at my barn

(SORRY TO HIJACK YOUR POST)