I tend to agree with Bob about Harley-Attitude-Davidson, but I don't think Morgan have a lot of choice. H-Ds make a good sound as long you are not trying to sleep, record, fish, or do any other peaceful pursuits like listening to a Jumbo Jet taking off! Other than that H-Ds are inefficient and woefully out of date and it is only the image and nostalgia which keep them in business.
Dickie is right though, the US market is very important so that engine is possibly a good choice, people know it, have spares, and the right tools (sledge hammers?!) and skills that can service them However, in the 1930s Gwenda Stewart set the record for a Morgan 3 at 116 MPH, 1 mph more than the new lump can manage, and probably half its size and weight. In fact that just proves how dated those H-Ds are!
Dickie, I will re-post the link on its own thread. All you have to do if you want to post it (or any other site) somewhere else is to open the page/site wait until it is fully loaded and active, then copy the details showing in the address bar near the top of your screen, then open up the page where you want it and copy it to there.